                                PRECEDENTIAL

  UNITED STATES COURT OF APPEALS
       FOR THE THIRD CIRCUIT
            _____________

                No. 13-1910
               _____________

      UNITED STATES OF AMERICA

                      v.

            RICHARD STANLEY,
                        Appellant
               _____________

On Appeal from the United States District Court
    for the Western District of Pennsylvania
      District Court No. 2-11-cr-00272-001
District Judge: The Honorable Joy Flowers Conti

            Argued January 7, 2014

 Before: SMITH, SHWARTZ, and SCIRICA,
              Circuit Judges

            (Filed: June 11, 2014 )
Donovan J. Cocas [ARGUED]
Rebecca R. Haywood
Office of United States Attorney
700 Grant Street
Suite 4000
Pittsburgh, PA 15219
       Counsel for Appellee

Lisa B. Freeland
Peter R. Moyers [ARGUED]
Office of Federal Public Defender
10001 Liberty Avenue
1500 Liberty Center
Pittsburgh, PA 15222
       Counsel for Appellant
                   ________________

                      OPINION
                  ________________

SMITH, Circuit Judge.
      Richard Stanley appeals from an order of the
United States District Court for the Western District of
Pennsylvania denying his motion to suppress evidence
that he was in possession of child pornography.
Specifically, Stanley argues that a Pennsylvania State
Police officer conducted a warrantless search when he
used a device called the “MoocherHunter” to trace
                           2
Stanley’s wireless signal from a neighbor’s unsecured
wireless router to its source inside Stanley’s home. For
the reasons that follow, we conclude that the use of the
MoocherHunter was not a search within the meaning of
the Fourth Amendment. Accordingly, we will affirm the
judgment of the District Court.1

                             I.
       On November 11, 2010, Corporal Robert Erdely
(“Erdely”), the head of the computer crime unit of the
Pennsylvania State Police (“PSP”), was investigating the
online distribution of child pornography when he
discovered a computer on the Gnutella peer-to-peer
network2 sharing 77 files that he suspected contained
child pornography. Based on information available to
any Gnutella user, Erdely determined that this computer
was using file-sharing software with a globally unique
identification               number                   of
“8754E6525772BA0134C4C6CACF12E300”                (“300
GUID”) and was connected to the Internet via an Internet


1
       Judge Shwartz joins Parts I through IV.A of this
Opinion.
2
       Peer-to-peer networks allow users to share files by
connecting to other individual computers directly, without
using a centralized administrative system. Gnutella is a
particularly large peer-to-peer network and is utilized by a
number of popular file sharing programs.
                             3
protocol address (“IP address”) of “98.236.6.174” (“174
IP Address”).

      Through a search of publicly available records,
Erdely determined that the 174 IP Address was registered
to a Comcast Cable (“Comcast”) subscriber, and he
obtained a court order requiring Comcast to disclose this
individual’s subscription information.     In response,
Comcast informed Erdely of the subscriber’s name (“the
Neighbor”) and his home address in Pittsburgh,
Pennsylvania.

      On November 18, 2010, Erdely executed a search
warrant for the Neighbor’s home. The search revealed
that none of the Neighbor’s computers contained either
child pornography or the file-sharing software with the
300 GUID. The search also revealed that the Neighbor’s
wireless Internet router was not password-protected.
From this information, Erdely deduced that the computer
sharing child pornography was connecting wirelessly to
the Neighbor’s router from a nearby location without the
Neighbor’s knowledge or permission.3 In other words,


3
       To establish a wireless connection, an Internet user
selects the desired wireless network from a list of available
options displayed on his wireless-enabled device. This causes
a wireless card inside the user’s device to transmit radio
waves to the wireless router, which then transmits radio
waves back to the device. This exchange of radio waves
                             4
Erdely determined that the computer in question was
“mooching” off the Neighbor’s Internet connection.

       With the Neighbor’s permission, Erdely connected
a police computer to the router in order to determine the
media access control address (“MAC address”) and
private IP address of any other devices that were
connected wirelessly at the time.4 From this data, Erdely
determined that the mooching computer was not
connected at that time. With the Neighbor’s permission,
Erdely left the police computer attached to the router so it
could be accessed remotely from Erdely’s office in
Harrisburg, Pennsylvania.

       On January 19, 2011, while working in Harrisburg,
Erdely learned that the computer associated with the 300
GUID was again sharing child pornography on the IP
address assigned to the Neighbor. By remotely accessing
the police computer he had left in the Neighbor’s home,
Erdely determined that the mooching computer had a
private IP address of “192.168.2.114” (the “114 Private
IP Address”) and a MAC address of “mac=00-1C-B3-
B4-48-95” (the “95 MAC Address”). Erdely searched
online for the “mac” prefix in the 95 MAC address and
discovered that it belonged to an Apple wireless card.

comprises the “wireless signal” that connects the device to the
router.
4
        This information was available to any computer
connected to the Neighbor's router.
                              5
Because Erdely had not discovered any Apple wireless
devices in the Neighbor’s home, this information
reinforced his conclusion that the 95 MAC Address and
the 114 Private IP Address belonged to the mooching
computer. Erdely decided to travel to Pittsburgh so that
he could use a “MoocherHunter” device to attempt to
determine this computer’s location.

       The aptly-vernacularized MoocherHunter is a
mobile tracking software tool that can be downloaded for
free from the manufacturer’s website and used by anyone
with a laptop computer and a directional antenna.5 This
device can be used in either “active mode” or “passive
mode.” In “passive mode,” the user enters the MAC
address of the wireless card he wishes to locate and the
program measures the signal strength of the radio waves
emitted from this card.6 These signal strength readings
increase as the user aims the antenna in the direction of
the mooching computer and moves closer to its location.
       Before using the MoocherHunter, Erdely contacted
an Assistant United States Attorney in the Western
District of Pennsylvania to discuss the propriety of

5
       Though MoocherHunter is the name of the software,
for the sake of convenience this opinion will refer to this
software and the equipment using it collectively as “the
MoocherHunter.”
6
       The mechanics of “active mode” are not relevant to
this appeal.
                            6
obtaining a search warrant.7 Erdely and the AUSA had a
“lengthy discussion” in which they decided that the
MoocherHunter was “completely different” from the
infrared technology used in Kyllo v. United States, 537
U.S. 27 (2001). J.A. 271. They also discussed the
practical impossibility of obtaining a search warrant
without knowing which one of the many nearby
residences the signal was being transmitted from.
Ultimately, Erdely determined that he needed to proceed
without a warrant.

       On the evening of January 19, 2011, Erdely arrived
at the Neighbor’s home and entered the 95 MAC Address
into the MoocherHunter. From the residence, he found
that the MoocherHunter’s readings were strongest (67)
when he aimed the antenna at a six-unit apartment
complex across the street. From the public sidewalk in
front of this building, the MoocherHunter’s readings
were strongest (100) when Erdely aimed the antenna
directly at Stanley’s apartment.
      That night, Erdely used this information to obtain a
search warrant for Stanley’s home. Shortly thereafter,
Erdely and other PSP officers executed this warrant.
When these officers arrived, Stanley initially fled through
a back door. He soon returned, however, and confessed

7
       Ederly reached out to the AUSA after unsuccessfully
attempting to contact an attorney at the Allegheny County
District Attorney’s Office.
                            7
that he had connected to the Neighbor’s router to
download child pornography. Erdely seized Stanley’s
Apple laptop and later recovered 144 images and video
files depicting child pornography.

                            II.

        As a result of Erdely’s meticulous investigation, a
federal grand jury in the Western District of
Pennsylvania returned a one-count indictment charging
Stanley with possession of child pornography in violation
of 18 U.S.C. § 2252(a)(4)(B). Stanley was arrested and
initially pled not guilty.
       On April 13, 2012, Stanley filed a motion to
suppress his statements to Erdely and the evidence
obtained from his home and computer. His primary
argument was that Erdely conducted a warrantless search
under Kyllo v. United States, 533 U.S. 27 (2001), when
he used the MoocherHunter to obtain information about
the interior of his home that was unavailable through
visual surveillance.8
      On November 14, 2012, the District Court denied
Stanley’s motion. Citing Smith v. Maryland, 442 U.S.
8
       Stanley also argued that Erdely’s search warrant was
not supported by probable cause and that the MoocherHunter
was a “mobile tracking device” which required a warrant
under 18 U.S.C. § 3117. He has abandoned these arguments
on appeal.
                            8
735 (1979), the District Court held that Stanley lacked a
reasonable expectation of privacy in his wireless signal
because he “exposed his wireless signal to a third party
and assumed the risk that the signal would be revealed to
authorities.” J.A. 23. The District Court also rejected
Stanley’s Kyllo argument, explaining that “although the
defendant [in Kyllo] caused the heat by using high-
intensity lamps, he did not send it to a third party and to
the extent he could, he contained the heat in his garage.”
Id. at 27. Stanley, on the other hand, “had to . . . initiate
contact” with the Neighbor’s router and therefore “did
not have a reasonable expectation of privacy in that
wireless signal simply because it emanated from a
computer located inside of his home.” Id. Finally, the
District Court noted that if Stanley had shared child
pornography through his own Internet subscription,
Erdely could have discovered his location the same way
he discovered the Neighbor’s: by subpoenaing his
Internet service provider for subscription information.
Id. at 28. “That [Stanley] established an unauthorized
connection,” the District Court reasoned, “does not
convert his subjective expectation of privacy into a
reasonable one.” Id.

      Thereafter, Stanley entered into an agreement with
the government, under which he would plead guilty but
reserve the right to appeal the District Court’s order
denying his motion to suppress. After his guilty plea was
entered, the District Court sentenced Stanley to 51
                             9
months in prison. This timely appeal followed.
                           III.

      The District Court had subject matter jurisdiction
pursuant to 18 U.S.C. § 3231. We have jurisdiction
under 28 U.S.C. § 1291.

       “With respect to a suppression order, we review
the District Court’s factual findings for clear error and
exercise plenary review over its legal determinations.”
United States v. Ritter, 416 F.3d 256, 261 (3d Cir. 2005)
(internal citations omitted).
                           IV.

       “There are two ways in which the government’s
conduct may constitute a ‘search’ implicating the Fourth
Amendment.” Free Speech Coal., Inc. v. Att’y Gen. of
U.S., 677 F.3d 519, 543 (3d Cir. 2012). First, a search
occurs when the government “unlawfully, physically
occupies private property for the purpose of obtaining
information.” Id. (citing United States v. Jones, 132
S.Ct. 945, 949–52 (2012)). Alternatively, a search occurs
when the government violates an individual’s expectation
of privacy that “society recognizes as reasonable.” Kyllo,
533 U.S. at 33 (citing Katz v. United States, 389 U.S.
347, 361 (1967) (Harlan, J., concurring)).



                           10
       Stanley does not contend that Erdely physically
trespassed on his property at any point during his
investigation. Nor would that argument have been
successful; Erdely did not physically enter Stanley’s
property until after he obtained a search warrant for the
apartment. Instead, Stanley argues that Erdely violated
his reasonable expectation of privacy when he used the
MoocherHunter to trace Stanley’s wireless signal back to
the interior of his home.

        Determining whether this second type of search
occurred involves two questions: “(1) whether the
individual demonstrated an actual or subjective
expectation of privacy in the subject of the search or
seizure; and (2) whether this expectation of privacy is
objectively justifiable under the circumstances.” Free
Speech Coal., Inc., 677 F.3d at 543. To be objectively
justifiable, a defendant’s expectation of privacy must be
more than rational; society must be willing to recognize it
as legitimate. See United States v. Jacobsen, 466 U.S.
109, 122 (1984) (“The concept of an interest in privacy
that society is prepared to recognize as reasonable is, by
its very nature, critically different from the mere
expectation, however well justified, that certain facts will
not come to the attention of the authorities.”); Rakas v.
Illinois, 439 U.S. 128, 143 n.12 (1978) (“Obviously,
however, a ‘legitimate’ expectation of privacy by
definition means more than a subjective expectation of
not being discovered.”).
                            11
                             A.
       The thrust of Stanley’s argument on appeal is that
Erdely’s use of the MoocherHunter was an unlawful
search under Kyllo. We disagree, and hold that Stanley’s
expectation of privacy is not one that society is prepared
to recognize as legitimate.9

       In Kyllo, police officers suspected that the
defendant was growing marijuana inside of his home.
533 U.S. at 29. Without obtaining a warrant, these
officers parked across the street and scanned the
defendant’s home using a thermal imager. Id. at 29–30.
This device revealed that certain portions of the home’s
exterior were unusually warm, leading police to believe
that the defendant was using high-powered halide lamps
inside. Id. at 30. The Supreme Court held that this scan
was a search, and established a rule that “obtaining by
sense-enhancing technology any information regarding
the interior of the home that could not otherwise have
been obtained without physical intrusion into a
constitutionally protected area constitutes a search—at
least where (as here) the technology in question is not in

9
        The Government argues that Stanley did not proffer
any evidence of a subjective expectation of privacy. Because
we find that any such expectation would not have been
objectively justifiable, we need not reach the question of
whether Stanley adequately demonstrated that he subjectively
held it.
                            12
general public use.” Id. at 34 (internal quotation marks
and citation omitted).

       One could argue that this language, considered in
the abstract, encompasses Erdely’s use of the
MoocherHunter. The MoocherHunter, like the thermal
imager in Kyllo, is surely “sense-enhancing technology,”
as it detects radio waves which cannot be perceived by
unaided human senses. Further, Erdely used this sense-
enhancing technology to obtain “information regarding
the interior of [Stanley’s] home that could not otherwise
have been obtained without physical intrusion”: the fact
that a wireless card associated with particular Internet
activity was located there. Id. See also United States v.
Karo, 468 U.S. 705, 714–18 (1984) (holding that the
government’s use of a tracking device to discover that a
particular barrel was located inside the defendant’s home
was a search for purposes of the Fourth Amendment).
Finally, the government does not contend that the
MoocherHunter is technology that is “in general public
use.”
       Critical to Kyllo’s holding, however, was the fact
that the defendant sought to confine his activities to the
interior of his home. He justifiably relied on the privacy
protections of the home to shield these activities from
public observation.        See Kyllo, 533 U.S. at 34
(characterizing the thermal imaging scan as a “search of
the interior of [Kyllo’s] home[],” which it considered to
be “the prototypical . . . area of protected privacy”). See
                            13
also id. at 37 (“In the home, our cases show, all details
are intimate details, because the entire area is held safe
from prying government eyes.”) (emphasis in original).
Stanley can make no such claim.

       Stanley made no effort to confine his conduct to
the interior of his home. In fact, his conduct—sharing
child pornography with other Internet users via a
stranger’s Internet connection—was deliberately
projected outside of his home, as it required interactions
with persons and objects beyond the threshold of his
residence. In effect, Stanley opened his window and
extended an invisible, virtual arm across the street to the
Neighbor’s router so that he could exploit his Internet
connection. In so doing, Stanley deliberately ventured
beyond the privacy protections of the home, and thus,
beyond the safe harbor provided by Kyllo. See United
States v. Broadhurst, No. 3:11-cr-00121-MO-1, 2012
WL 5985615, at *5 (D. Or. Nov. 28, 2012)
(distinguishing the use of a MoocherHunter-like device
from the thermal scan in Kyllo because “in Kyllo, the heat
signals were not being intentionally sent out into the
world to connect publicly with others.”); United States v.
Norris, No. 2:11-cr-00188-KJM, 2013 WL 4737197, at
*7 (E.D. Cal. Sept. 3, 2013) (“In this case the agents used
Moocherhunter to pick up signals the defendant was
voluntarily transmitting to [his neighbor’s router], not
information confined to the private area of defendant’s
home.”).
                            14
       Stanley cannot avail himself of the privacy
protections of his home merely because he initiated his
transmission from there. See Smith, 442 U.S. at 743
(“The fact that [Smith] dialed the number on his home
phone rather than on some other phone could make no
conceivable difference, nor could any subscriber
rationally think that it would.”). Most importantly, while
Stanley may have justifiably expected the path of his
invisible radio waves to go undetected, society would not
consider this expectation “legitimate” given the
unauthorized nature of his transmission. Rakas, 439 U.S.
at 143 n.12.

       As noted in Rakas, “[a] burglar plying his trade in
a summer cabin during the off season may have a
thoroughly justified subjective expectation of privacy,
but it is not one which the law recognizes as
‘legitimate.’” Id. The defendant’s presence in those
circumstances “is wrongful; his expectation is not one
that society is prepared to recognize as reasonable.” Id.
(internal quotation marks and citation omitted).
Similarly, in United States v. Kennedy, 638 F.3d 159, 165
(3d Cir. 2011), we held that an unauthorized driver in a
rental car lacks a reasonable expectation of privacy in the
vehicle in part because he “not only acts in contravention
of the owner’s property rights, but also deceives the
owner of the vehicle.”


                            15
        Here, the presence of Stanley’s unauthorized
signal was itself “wrongful.” When Stanley deliberately
connected to the Neighbor’s unsecured wireless network,
he essentially hijacked the Neighbor’s router, forcing it to
relay data to Comcast’s modem and back to his
computer, all without either the Neighbor’s or Comcast’s
knowledge or consent. Stanley was, in effect, a virtual
trespasser. As such, he can claim no “legitimate”
expectation of privacy in the signal he used to effectuate
this trespass—at least where, as here, the MoocherHunter
revealed only the path of this signal and not its contents.

      The presence of Stanley’s signal was likely illegal.
A large number of states, including Pennsylvania, have
criminalized unauthorized access to a computer
network.10 A number of states have also passed statutes
penalizing theft of services,11 which often explicitly

10
       See, e.g., Cal. Penal Code § 502; Colo. Rev. Stat. Ann.
§ 18-5.5-102; Del. Code Ann. tit. 11, § 932; Fla. Stat. Ann. §
815.06; Ind. Code Ann. § 35-43-2-3; Iowa Code Ann. §
716.6B; La. Rev. Stat. Ann. § 14:73.8; Mo. Ann. Stat. §
569.099; N.H. Rev. Stat. Ann. § 638:17; N.J. Stat. Ann. §
2C:20-25; Okla. Stat. Ann. tit. 21, § 1953; S.C. Code Ann. §
16-16-20; 18 Pa. Cons. Stat. Ann § 7611; Tex. Penal Code
Ann. § 33.02; Vt. Stat. Ann. tit. 13, § 4102; W. Va. Code
Ann. § 61-3C-5.
11
       See, e.g., Ala. Code § 13A-8-10; Ariz. Rev. Stat. Ann.
§ 13-1802; Del. Code Ann. tit. 11, § 845; 720 ILCS 5/16-14;
Ky. Rev. Stat. Ann. § 514.060; Mont. Code Ann. § 45-6-305;
                             16
include telephone, cable, or computer services.12 We
need not decide here whether these statutes apply to
wireless mooching,13 but the dubious legality of Stanley’s
conduct bolsters our conclusion that society would be
unwilling to recognize his privacy interests as
“reasonable.” This is particularly so where the purpose

N.H. Rev. Stat. Ann. § 637:8; N.J. Stat. Ann. § 2C:20-8; 18
Pa. Cons. Stat. Ann. § 3926; Utah Code Ann. § 76-6-409.3;
Vt. Stat. Ann. tit. 13, § 2582.
12
       See, e.g., Ariz. Rev. Stat. Ann. § 13-1801; Del. Code
Ann. tit. 11, § 857; N.J. Stat. Ann. § 2C:20-8; Or. Rev. Stat.
Ann. § 164.125; Wash. Rev. Code Ann. § 9A.56.010; 18 Pa.
Cons. Stat. Ann. § 3926. See also Alaska Stat. Ann. §
11.46.200 (“A person commits theft of services if . . . the
person obtains the use of . . . a computer network . . . with
reckless disregard that the use by that person is
unauthorized.”); Iowa Code Ann. § 714.1 (“A person
commits theft when the person . . . [k]nowingly and without
authorization accesses . . . a . . . computer network . . . for the
purpose of obtaining computer services.”).
13
       Some commentators consider the legality of wireless
mooching to be an open question. See, e.g., Grant J. Guillot,
Trespassing Through CyberSpace; Should Wireless
Piggybacking Constitute a Crime or Tort Under Louisiana
Law?, 69 La. L. Rev. 389, 399 (2009); Benjamin D. Kern,
Whacking, Joyriding and War-Driving: Roaming Use of WI-
FI and the Law, 21 Santa Clara Computer & High Tech. L.J.
101, 145 (2004); Matthew Bierlein, Note, Policing the
Wireless World: Access Liability in the Open Wi-Fi Era, 67
Ohio St. L.J. 1123, 1165 (2006).
                                17
of Stanley’s unauthorized connection was to share child
pornography.14

       To recognize Stanley’s expectation of privacy as
“legitimate” would also reward him for establishing his
Internet connection in such an unauthorized manner. As
the District Court recognized, had Stanley shared child
pornography using his own, legitimate Internet
connection, Erdely could have obtained Stanley’s address
from his Internet service provider—just as he obtained
the Neighbor’s address from Comcast. See United States
v. Christie, 624 F.3d 558, 573–74 (3d Cir. 2010)
(“Federal courts have uniformly held that subscriber
information provided to an internet provider is not
protected by the Fourth Amendment’s privacy
expectation.”) (internal quotation marks and citations
omitted).    Stanley cannot conceal his location by
establishing an unauthorized connection and at the same
time ask society to validate his expectation of privacy in
the signal-strength information that police used to
determine that location in a more roundabout manner.
See Broadhurst, 2012 WL 5985615 at *5 (refusing to
allow the defendant to “serendipitously receive Fourth
Amendment protection because he hijacked another
person’s Internet connection to share child pornography
14
       Cf. La. Rev. Stat. Ann. § 14:73.8 (penalizing
“accessing . . . of any . . . computer network . . . for purposes
of uploading, downloading, or selling of pornography
involving juveniles”).
                               18
files”).
       Although the analogy is imperfect, we believe that
the MoocherHunter is akin to a drug sniffing dog in that
it was only able to detect a signal that was itself
unauthorized and likely illegal. The use of a drug
sniffing dog, which allows police to detect odors that
they could not perceive with their human senses, is not a
search under the Fourth Amendment because it
“discloses only the presence or absence of narcotics, a
contraband item.” United States v. Place, 462 U.S. 696,
707 (1983). See also id. (“[A drug sniffing dog] does not
expose noncontraband items that otherwise would remain
hidden from public view, as does, for example, an
officer’s rummaging through the contents of the
luggage.”).    In this way, “the manner in which
information is obtained through this investigative
technique is much less intrusive than a typical search.”
Id. Thus, “[t]he legitimate expectation that information
about perfectly lawful activity will remain private is
categorically distinguishable from [a defendant’s] hopes
or expectations concerning the nondetection of
contraband.” Illinois v. Caballes, 543 U.S. 405, 410
(2005).

      Here, the MoocherHunter detected only a signal
that was itself unauthorized, and as we have
characterized it, likely illegal. At the time Erdely used
the MoocherHunter, Stanley was connecting to the
Neighbor’s router without his knowledge or consent.
                           19
Without that contemporaneous unauthorized connection,
the MoocherHunter would have been unable to function.
And the MoocherHunter revealed only the path of the
signal establishing this connection. It revealed nothing
about the content of the data carried by that signal.
Accordingly, Stanley’s privacy expectations concerning
the path of his unauthorized signal are “categorically
distinguishable” from expectations he would have had
concerning the path of a lawful, legitimate signal.
Caballes, 543 U.S. at 410.

                             B.

       While we conclude that Stanley lacked a
reasonable expectation of privacy in the path of his
unauthorized signal, we believe the able District Judge
went too far when she held that “Stanley exposed his
signal to a third party and assumed the risk that the signal
would be revealed to the authorities.” J.A. 23. Other
district courts have embraced this theory as well. See
Norris, 2013 WL 4737197 at *7–8; Broadhurst, 2012
WL 5985615 at *5. Because of that, we believe it
appropriate to address why we consider this a flawed
approach.15

15
       Because we hold that Stanley lacked a reasonable
expectation of privacy, Judge Shwartz finds it unnecessary to
discuss the third-party doctrine and Smith v. Maryland. In
addition, Judge Shwartz has a different view concerning the
doctrine’s applicability to the facts of this case. From her
                             20
      In Smith, a robbery victim told police that she was
receiving harassing phone calls from a man identifying
himself as the robber. 442 U.S. at 737. Suspecting this
man to be Michael Smith, police asked Smith’s telephone
company to install a pen register that would record the
phone numbers he dialed from his home phone. Id.
When the register confirmed that Smith had dialed the
victim’s number, police obtained a search warrant for his
home and discovered additional incriminating evidence.
Id. After he was indicted, Smith moved to suppress this
evidence on the basis that police officers conducted an
unconstitutional warrantless search. Id.


perspective, even though Stanley’s transmissions to the
Neighbor’s router did not specifically disclose his location, he
voluntarily disclosed information to surreptitiously obtain his
neighbor’s internet service that his neighbor could use to find
him. A cybertrespasser like Stanley assumes the risk that his
neighbor (the trespassed upon party) would take steps to
discover his whereabouts and share whatever clues he has
with the police, including those that provide a link that leads
to his location. Like a footprint, the information that Stanley
conveyed to the neighbor’s router may not in and of itself
disclose his location, but it did provide a lead and by leaving
it behind, Stanley assumed the risk it would be pursued.
Thus, to the extent it is necessary to discuss the third-party
doctrine, Judge Shwartz would conclude that, on the facts of
this case, it provides another ground on which to affirm the
District Court’s ruling that the use of the MoocherHunter here
did not violate the Fourth Amendment.
                              21
       In upholding Smith’s conviction, the Supreme
Court acknowledged that it “consistently has held that a
person has no legitimate expectation of privacy in
information he voluntarily turns over to third parties”
because that person “assume[s] the risk” that this third
party will convey this information to the police. Id. at
743–44 (internal citations omitted). As an example, the
Court cited its prior holding that “a bank depositor has no
legitimate expectation of privacy in financial information
voluntarily conveyed to banks and exposed to their
employees in the ordinary course of business.” Id. at 744
(internal quotation marks and citation omitted). The
Court then explained that “[w]hen he used his phone,
petitioner voluntarily conveyed numerical information to
the telephone company and ‘exposed’ that information to
its equipment in the ordinary course of business.” Id. at
744. Accordingly, “petitioner assumed the risk that the
company would reveal to police the numbers he dialed.”
Id.

       In Stanley’s case, the District Court held that
“[b]ased upon Smith’s rationale, . . . Stanley did not have
a legitimate expectation of privacy in the wireless signal
he caused to emanate from his computer to the
Kowikowski wireless router.” J.A. 20. The District
Court explained:

      The information logged on that wireless
      router was accessible to [the Neighbor] and
                            22
      through his consent, to Erdely.            This
      information showed the private IP address of
      Stanley’s computer.       Stanley, therefore,
      could have no reasonable expectation of
      privacy in the signal he was sending to or
      receiving from [the Neighbor]’s wireless
      router in order to connect to the internet.

J.A. 21. Accordingly, the District Court held that
“Stanley exposed his wireless signal to a third party and
assumed the risk that the signal would be revealed to the
authorities.” J.A. 23.

       We regard the District Court’s reasoning as flawed
because Stanley’s wireless signal was not itself
“information” that could be “conveyed” to authorities.
Smith, 442 U.S. at 744. Rather, his wireless signal was
composed of radio waves that were associated with a
plethora of information, some of which the Neighbor
could convey to authorities, but most of which he could
not. Specifically, Stanley, through transmission of his
wireless signal, disclosed to the Neighbor his MAC
address, his private IP address, and the fact that his
wireless card was communicating with Stanley’s router at
particular points in time. Stanley, therefore, assumed the
risk that the Neighbor would convey this information to
Erdely.


                            23
       Erdely, however, did not simply take this
information to a magistrate and obtain a search warrant.
Rather, Erdely used this information to conduct an
additional investigative step that revealed additional
information. Specifically, Erdely entered Stanley’s MAC
address into a sense-enhancing device, which he then
used to obtain additional information about the strength
of Stanley’s signal at different physical locations. It was
this additional information that Erdely used to obtain a
warrant for Stanley’s home. Yet Stanley did not “assume
the risk” that the Neighbor would divulge this
information because the Neighbor never possessed it.
And if the Neighbor had possessed it, Erdely would not
have needed the MoocherHunter in the first place.16

      Were we to hold that Stanley exposed his “signal”
under Smith by transmitting it to a third-party router, we
might open a veritable Pandora’s Box of Internet-related

16
       The District Court also appears to have erroneously
equated Stanley’s wireless signal with the private IP address
assigned to that signal. See J.A. 21 (“An internet subscriber
does not have a reasonable expectation of privacy in his IP
address . . . , and likewise, a person connecting to another
person’s wireless router does not have an expectation of
privacy in that connection, i.e. the private IP address, when it
is available to that third person and anyone with whom that
person shares the information.”). Just as a home is more than
the address assigned to it, a wireless signal, as discussed
above, is more than just its private IP address.
                              24
privacy concerns. The Internet, by its very nature,
requires all users to transmit their signals to third parties.
Even a person who subscribes to a lawful, legitimate
Internet connection necessarily transmits her signal to a
modem and/or servers owned by third parties. This
signal carries with it an abundance of detailed, private
information about that user’s Internet activity. A holding
that an Internet user discloses her “signal” every time it is
routed through third-party equipment could, without
adequate qualification, unintentionally provide the
government unfettered access to this mass of private
information without requiring its agents to obtain a
warrant. We doubt the wisdom of such a sweeping
ruling, and in any event, find it unnecessary to embrace
its reasoning.

                             V.

       We conclude that Stanley lacked a reasonable,
legitimate expectation of privacy in the wireless signal.
While Stanley is neither sheltered by Kyllo nor defeated
by Smith, the unauthorized nature of his connection to the
Neighbor’s router eliminates the possibility that society
would recognize his privacy expectations as legitimate.
Accordingly, we will affirm the judgment of the District
Court.




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