                               In the

    United States Court of Appeals
                 For the Seventh Circuit
                     ____________________
No. 16-1029
JEFFREY ALLEN, et al.,
                                               Plaintiffs-Appellants,

                                  v.

CITY OF CHICAGO,
                                                 Defendant-Appellee.
                     ____________________

         Appeal from the United States District Court for the
            Northern District of Illinois, Eastern Division.
        No. 10 C 3183 — Sidney I. Schenkier, Magistrate Judge.
                     ____________________

      ARGUED APRIL 6, 2017 — DECIDED AUGUST 3, 2017
                 ____________________

   Before EASTERBROOK, MANION, and HAMILTON, Circuit
Judges.
   HAMILTON, Circuit Judge. This appeal arises from a Fair La-
bor Standards Act collective action. Plaintiffs are current and
former members of the Chicago Police Department’s Bureau
of Organized Crime who claim that the Bureau did not com-
pensate them for work they did off-duty on their mobile elec-
tronic devices (BlackBerrys). The case was tried to the court,
Magistrate Judge Schenkier, presiding by consent under 28
2                                                   No. 16-1029

U.S.C. § 636(c). The judge issued detailed findings of fact and
conclusions of law in favor of the Bureau, finding that it did
not prevent plaintiffs from requesting payment for such non-
scheduled overtime work and did not know that plaintiffs
were not being paid for it. Plaintiffs appeal, but we find no
persuasive reason to upset the judgment of the district court.
We affirm the judgment for the Bureau.
I. The Fair Labor Standards Act
    We begin by explaining the standards that apply under the
Fair Labor Standards Act when an employer asserts that it did
not know of the overtime work for which employees claim
they were not paid. The Act, codified as 29 U.S.C. § 201 et seq.,
requires employers to pay covered employees at one-and-a-
half times their usual pay rate if they are employed for longer
than a certain hourly threshold. That threshold is usually
forty hours per week. § 207(a)(1). For law enforcement em-
ployees like these plaintiffs, the threshold is one hundred and
seventy-one hours per twenty-eight day period. § 207(a)(1) &
(k); 29 C.F.R. § 553.230(b).
    The statute defines “employ” broadly, as “to suffer or per-
mit to work.” § 203(g). That broad definition is central to the
purpose of the Act. It helps prevent evasion by employers
who might seek to issue formal written policies limiting over-
time that are widely violated, or who might deliberately close
their eyes to overtime work their employees are doing. See
Kellar v. Summit Seating Inc., 664 F.3d 169, 177 (7th Cir. 2011)
(employer cannot “sit back and accept” work without com-
pensating it, even if employer has rules against overtime
work), quoting 29 C.F.R. § 785.13. Employers must, as a result,
pay for all work they know about, even if they did not ask for
the work, even if they did not want the work done, and even
No. 16-1029                                                   3

if they had a rule against doing the work. Id., citing Chao v.
Gotham Registry, Inc., 514 F.3d 280, 288 (2d Cir. 2008). If the
employer does not want to pay overtime, its management
must “exercise its control and see that the work is not per-
formed.” 29 C.F.R. § 785.13.
   That strict rule has a limit, however. It “stops short of re-
quiring the employer to pay for work it did not know about,
and had no reason to know about.” Kellar, 664 F.3d at 177. The
employer’s knowledge can be either actual or constructive. Id.
An employer has constructive knowledge of an employee’s
work if it should have acquired knowledge of that work
through reasonable diligence. Hertz v. Woodbury County, 566
F.3d 775, 781 (8th Cir. 2009).
    One way an employer can exercise diligence is by estab-
lishing a reasonable process for an employee to report uncom-
pensated work time. That principle has been at least implicit
in our cases. In Gaines v. K-Five Construction Corp., 742 F.3d
256, 271 (7th Cir. 2014), for example, we affirmed summary
judgment for an employer that did not know the plaintiff was
working overtime. We reasoned, in part, that although the
employer gave its employees a form on which to record their
time, the plaintiff did not use the form as intended: he noted
the overtime in a margin note on the wrong part of the form
and omitted it when completing the appropriate section. That
misuse prevented an inference that the employer knew about
the overtime. Id.
    The Sixth and Ninth Circuits have been more explicit, af-
firming summary judgment for employers who set up pro-
cesses for reporting overtime that the plaintiffs did not use.
White v. Baptist Memorial Health Care Corp., 699 F.3d 869, 876
(6th Cir. 2012) (affirming summary judgment for employer:
4                                                     No. 16-1029

“When the employee fails to follow reasonable time reporting
procedures she prevents the employer from knowing its obli-
gation to compensate the employee … .”); Forrester v. Roth’s
I.G.A. Foodliner, Inc., 646 F.2d 413, 414 (9th Cir. 1981) (affirming
summary judgment for employer: “where an employer has no
knowledge that an employee is engaging in overtime work
and that employee … deliberately prevents the employer
from acquiring knowledge … , the employer’s failure to pay
… is not a violation of [§] 207”). We agree with their reason-
ing.
    But an employer’s formal policy or process for reporting
overtime will not protect the employer if the employer pre-
vents or discourages accurate reporting in practice. White, 699
F.3d at 876 (distinguishing cases “where the employer pre-
vented the employees from reporting overtime”). Such em-
ployer misbehavior might be overt. In Allen v. Board of Public
Education, 495 F.3d 1306, 1316 (11th Cir. 2007), for example,
plaintiff-employees were told that they should not record
their overtime hours and that their employer would not pay
overtime. Accurate time sheets were rejected, torn up, or ed-
ited. Or the employer might be more subtle. In Brennan v. Gen-
eral Motors Acceptance Corp., 482 F.2d 825, 827 (5th Cir. 1973),
the employees’ jobs demanded “long and irregular hours,”
but their supervisors “insisted that all work be completed
within certain defined time limits.” The employer’s practices
effectively “squelched truthful responses” in overtime re-
ports. Id. at 827–28.
II. Factual and Procedural Background
   With that legal background, we turn to the facts of this
case, which comes to us following a trial to the court. We
No. 16-1029                                                       5

therefore review the district court’s factual findings deferen-
tially, and our account of the facts tracks its factual findings.
See Fed. R. Civ. P. 52(a)(6) (“Findings of fact … must not be set
aside unless clearly erroneous … .”). We focus especially on
the court’s findings about the Bureau’s knowledge of plain-
tiffs’ overtime reporting, the issue central to the district court’s
decision and this appeal.
    This case was brought by Jeffrey Allen and fifty-one other
opt-in plaintiffs. Plaintiffs are current or former members of
the Chicago Police Department’s Bureau of Organized Crime.
(Although the City of Chicago is the defendant here, the focus
is on practices specific to the Bureau, though we must con-
sider some actions of the larger Chicago Police Department.)
The Bureau is a prestigious assignment for Chicago police of-
ficers. Its members conduct sophisticated investigations into,
for example, gangs, narcotics trafficking, and human traffick-
ing. Although members have scheduled shifts, the nature of
their work sometimes requires them to work outside their
shifts during what would otherwise be off-duty time. The po-
lice department issued plaintiffs mobile electronic devices
(BlackBerrys), which they sometimes used in their off-duty
work. This suit is over whether they were appropriately com-
pensated for off-duty work on their BlackBerrys.
    The police department has a process that officers use to
obtain overtime compensation: they submit “time due slips”
to their supervisors. The slips are small; there is some space
for explaining what work was done, and officers usually put
a short, vague phrase in the space. The slip does not ask how
the work was done, and officers do not typically include that
information. Supervisors approve the time, and the slips are
sent to payroll and processed. Plaintiffs regularly used that
6                                                           No. 16-1029

system; the fifty-two plaintiffs collectively reported and re-
ceived pay for three to four thousand overtime hours per year
from 2011 to 2014. But during the period relevant to this suit,
many plaintiffs did not submit slips for off-duty work done
on mobile electronic devices.
     The central question in the trial court was whether plain-
tiffs were prevented or discouraged from submitting slips by
an unwritten policy of the Bureau’s.1 The district court certi-
fied an FLSA collective action before discovery, then after dis-
covery refused to decertify the collective action, denied sum-
mary judgment, and held a bench trial. After a six-day bench
trial, the court ruled for the Bureau in a thorough memoran-
dum opinion.
    The court resolved several preliminary questions before
addressing whether the Bureau had the unwritten policy
plaintiffs alleged. The court agreed with plaintiffs that some
of their off-duty BlackBerry activity was work that was com-
pensable under the FLSA. It acknowledged evidence that Bu-
reau supervisors knew plaintiffs sometimes worked off-duty
on their BlackBerrys. But the court also found that the super-
visors did not know or have reason to know that plaintiffs
were not submitting slips and therefore were not being paid
for that work. Although supervisors in theory could have
checked what they knew of plaintiffs’ off-duty work against
the time slips they approved, the court found that requiring
them to do so would be impractical: supervisors approved a

    1  Plaintiffs tell us that they did not specify whether the policy was
written or unwritten; they attribute the “unwritten policy” framing to the
district court. Plaintiffs’ complaint did not refer to an unwritten policy,
but their response to the Bureau’s decertification motion did, as did their
pre- and post-trial proposed findings of fact.
No. 16-1029                                                     7

large number of slips per day, and slips were sometimes sub-
mitted and reviewed well after the work was performed.
Also, the court found, plaintiffs never told their supervisors
that they were not being paid for such work.
   The court then turned to the central question: whether
plaintiffs had shown the existence of an unwritten policy not
to compensate them for off-duty work performed on their
BlackBerrys. It considered four categories of plaintiffs’ evi-
dence of such a policy: evidence of (1) a Bureau-wide belief
that officers should not turn in slips for BlackBerry work; (2)
written policies to that effect; (3) pressure to reduce overtime
in general; and (4) pressure not to seek compensation for
BlackBerry work in particular.
     On the first point, the evidence was in conflict. Some plain-
tiffs testified that the Bureau’s culture would frown on sub-
mitting slips for BlackBerry work. But other Bureau officers,
including some plaintiffs, submitted slips for such work and
were never denied compensation. Some supervisors know-
ingly approved slips submitted for such work; others proba-
bly did so without knowing it since the slips did not indicate
whether the work was done on a BlackBerry or not. No one
ever told plaintiffs not to submit slips for that work, and no
one was ever reprimanded or disciplined for submitting such
slips. All told, the court concluded, the evidence did not bear
out the common culture plaintiffs alleged.
    Plaintiffs’ second point focused on four documents. The
first was a “General Order” issued by the Chicago Police De-
partment in October 2010. The order established “guidelines
and responsibilities” for officers using department-issued
electronic devices. The order said that officers were not re-
quired to use such devices while off-duty. It said that officers
8                                                     No. 16-1029

would not be compensated for such use except in two circum-
stances: if the officer was on a “call-back” assignment (a term
defined in collective bargaining agreements) or if a superior
directed and authorized overtime for the work. The order also
introduced the second significant document, a “Compliance
Statement,” to be signed when an officer received a device. By
signing, the officer acknowledged that he would “not be com-
pensated” for accessing the device off-duty except under the
same circumstances explained in the order.
    In 2013, the Department issued another General Order on
the same topic. It repeated many of the 2010 Order’s points
word-for-word. But instead of saying that officers would “not
be compensated” for off-duty device use except under certain
circumstances, it said that off-duty officers “will not use” de-
vices except under those circumstances. The Bureau’s chief is-
sued a memorandum to the Bureau’s deputy chief and com-
manders reiterating that the 2013 General Order applied to
the Bureau, although he did not distribute the memorandum
to lower-ranking officers.
     The district court wrestled with the orders, noting confu-
sion about what they were meant to accomplish and express-
ing disappointment that the Bureau never made a “simple
written statement” on compensation of BlackBerry work. De-
spite the confusion, the court made two important findings.
First, it rejected plaintiffs’ trial position on the orders. Plain-
tiffs contended that the orders required them either to obtain
a supervisor’s approval before working overtime or to forgo
compensation. The court disagreed, noting that the orders de-
scribed themselves as “guidelines” and that neither plaintiffs
nor the Bureau ever acted as though the orders required pre-
No. 16-1029                                                    9

approval of overtime. Second, in a lesson that might not sur-
prise students of organizational behavior, the court found that
the orders actually had no effect on plaintiffs or their supervi-
sors. The judge emphasized the uniform testimony to that ef-
fect, as well as the witnesses’ incomplete and inconsistent un-
derstandings of the orders’ meaning. As a result, the judge
found that the orders neither created a policy not to compen-
sate plaintiffs nor reaffirmed an existing unwritten policy.
    The third and fourth categories of plaintiffs’ evidence
posed fewer problems. The district court noted testimony that
the Bureau sporadically tried to reduce its officers’ overtime.
Supervisors occasionally discussed the topic and sent emails
to their subordinates about reducing overtime requests. This
was not a concerted effort, and it was unsuccessful. Total over-
time in the Bureau did not decrease, and plaintiffs’ overtime
increased over the relevant period. No plaintiff changed how
he or she handled overtime slips for BlackBerry work because
of these efforts. Nor did Bureau supervisors deter submission
of slips for BlackBerry work. Plaintiffs cited two examples of
alleged pressure, but both addressed overtime generally, not
BlackBerry work specifically, and neither became common
knowledge. Plaintiffs also emphasized that their supervisors
did not tell them to submit slips for BlackBerry work, but the
court found that the Bureau’s overtime procedure did not re-
quire such directions. Officers usually submitted slips with-
out being told to do so.
   After its discussion of plaintiffs’ arguments and the evi-
dence, the court found that plaintiffs had not shown that the
Bureau maintained an unwritten policy to deny them com-
pensation for off-duty BlackBerry work. It ruled in the Bu-
reau’s favor.
10                                                    No. 16-1029

III. Analysis
    Plaintiffs convinced the district court that they worked
overtime on their BlackBerrys. But plaintiffs also had to show
that the Bureau actually or constructively knew they were not
reporting that work. According to the district court, they
failed. We review the court’s legal conclusions de novo and its
factual findings for clear error. Isby v. Brown, 856 F.3d 508, 521
(7th Cir. 2017), citing Ernst v. City of Chicago, 837 F.3d 788, 795–
96 (7th Cir. 2016).
    Plaintiffs make two legal arguments: (1) that the district
court’s decision is unprecedented; and (2) that the district
court misapplied the constructive knowledge standard. But
their primary arguments are factual; they take an “any of the
above” approach to challenging the district court, arguing
that the Bureau actually knew about their underreporting, or
should have known, or caused it. Because they rely on the
same evidence to support each theory, we consider the theo-
ries together, although we do not consider several arguments
made for the first time on appeal.
     A. Legal Error
    Plaintiffs believe three of the district court’s findings make
this case unique: (1) that plaintiffs performed compensable
off-duty work; (2) that their supervisors knew about the work;
and (3) that their supervisors neither knew nor should have
known the plaintiffs were not compensated for that work. No
case in this or any other circuit, they claim, shares those fea-
tures. That is not correct. The district court cited such a case,
which plaintiffs do not attempt to distinguish: White v. Baptist
Memorial Health Care Corp. The plaintiff in that case, a nurse,
was not compensated for her meal breaks because she usually
No. 16-1029                                                               11

did not work during them. 699 F.3d at 872. If the meal break
was interrupted by work, she and her co-workers were sup-
posed to record their work in a log book to be paid for the
time. The employer also had a procedure employees could
use to report payroll errors. The plaintiff did not use either
process but later sued to be paid for interrupted meal breaks.
Id. at 872–73. Even though she sometimes told her supervisors
that she worked during her meal breaks, the district court
granted summary judgment for the employer and the Sixth
Circuit affirmed. The court reasoned that the plaintiff never
told anyone that she was not being paid for missing her meal
breaks, even though her employer had a reporting system and
did not prevent her using it. Id. at 876–77.
    White parallels what the district court found happened
here. Plaintiffs in this case, like the nurse in White, worked
time they were not scheduled to work, sometimes with their
supervisors’ knowledge. They had a way to report that time,
but they did not use it, through no fault of the employer, ac-
cording to the district court’s factual findings. Reasonable dil-
igence did not, in the district court’s view, require the em-
ployer to investigate further. Since, as we explain below, we
see no clear error in that view of the facts, we see no legal error
in reaching the same conclusion as the White court.2
   Plaintiffs also claim that the district court misapplied the
concept of constructive knowledge, but they are not clear
about what the court’s error was. Plaintiffs seem to contend


    2 The White panel was divided on whether the case should have been
resolved on summary judgment. See White, 699 F.3d at 879–84 (Moore, J.,
dissenting). In this case the trial record reveals genuine issues of material
fact that could not have supported summary judgment.
12                                                   No. 16-1029

that constructive knowledge should be found whenever the
employer could have known about uncompensated work
through, for example, examining all its records. In this case,
the Bureau could have discovered plaintiffs’ uncompensated
BlackBerry work by comparing the time slips to call and email
records the BlackBerrys generated, and so (plaintiffs reason)
it should be deemed to have had constructive knowledge of
the unpaid work.
    The Bureau contends that we need not address that argu-
ment. It reads White to hold that an employer’s constructive
knowledge is categorically irrelevant if its employee has in-
tentionally falsified his time records. White did not go that far.
It held that “if an employer establishes a reasonable process
for an employee to report uncompensated work time the em-
ployer is not liable for non-payment if the employee fails to
follow the established process.” Id. at 876. But White distin-
guished cases in which “the employer prevented the employ-
ees from reporting overtime or were otherwise notified of the
employees’ unreported work,” and listed several such cases.
Id. (collecting cases). The Bureau believes the court’s “other-
wise notified” language means that only an employer’s actual
knowledge suffices. But White’s list of example cases included
Reich v. Dep’t of Conservation & Natural Resources, 28 F.3d 1076,
1083–84 (11th Cir. 1994), which the White court characterized
as a case in which the “employer had constructive
knowledge.” 699 F.3d at 876. That undercuts the Bureau’s
broad interpretation.
   Moreover, such a broad interpretation of White equates
reasonable diligence with a reasonable reporting process, im-
plying that all an employer ever needs to do is establish a rea-
No. 16-1029                                                      13

sonable process for reporting overtime. We see no need to cre-
ate such a blanket rule. The requirements of reasonable dili-
gence depend on the facts of each case. White did not change
that, and neither do we.
     Nor do we accept plaintiffs’ position, which would break
still more sharply with established precedent. The reasonable
diligence standard asks what the employer should have
known, not what “it could have known.” Hertz, 566 F.3d at
782, citing Reich v. Stewart, 121 F.3d 400, 407 (8th Cir. 1997);
Craig v. Bridges Brothers Trucking LLC, 823 F.3d 382, 392 (6th
Cir. 2016) (“Some cases may lend themselves to a finding that
access to records would provide constructive knowledge of
unpaid overtime work, but that is not a foregone conclu-
sion.”) (quotation omitted); Newton v. City of Henderson, 47
F.3d 746, 749 (5th Cir. 1995) (holding, as a matter of law, that
employer’s access to records reflecting uncompensated over-
time “does not constitute constructive knowledge”). The dis-
trict court applied that standard correctly here.
   B. Waiver
    It is “well settled that arguments presented for the first
time on appeal are waived.” Bailey v. International Brotherhood
of Boilermakers, Iron Ship Builders, Blacksmiths, Forgers and Help-
ers, Local 374, 175 F.3d 526, 529 (7th Cir. 1999). That rule serves
several important purposes, including that it keeps appellate
courts from resolving questions “that require the factfinding
abilities of the district judge.” Id. at 530. The rule also protects
both parties’ ability to present evidence in support of their po-
sitions. See Singleton v. Wulff, 428 U.S. 106, 119–21 (1976) (re-
versing “unacceptable” appellate court decision to proceed to
merits questions not considered in trial court in part because
14                                                            No. 16-1029

losing party “has had no opportunity” to offer evidence or ar-
guments); cf. Rowe v. Gibson, 798 F.3d 622 (7th Cir. 2015) (di-
vided panel debating appropriateness of appellate court con-
ducting its own factual research), rehearing en banc denied
by equally divided court, 2015 WL 10767326 (7th Cir. Dec. 7,
2015).
    On appeal, plaintiffs have argued new factual theories, in-
cluding interpretations of the evidence not argued to the dis-
trict court.3 They argue, correctly, that we have discretion to
consider arguments raised for the first time on appeal. See
County of McHenry v. Insurance Co. of the West, 438 F.3d 813,
820 (7th Cir. 2006). We use that discretion rarely, however,
when the waiver “has caused no one—not the district judge,
not us, not the appellee—any harm of which the law ought to
take note.” Amcast Industrial Corp. v. Detrex Corp., 2 F.3d 746,
749 (7th Cir. 1993). We may use it “to entertain arguments that
turn on pure issues of law,” particularly arguments that
would have been foreclosed in the district court by binding
precedent. Hively v. Ivy Tech Community College of Indiana, 853
F.3d 339, 351 (7th Cir. 2017) (en banc). Plaintiffs’ arguments
are not in that category. They would require us in effect to re-
try the case on a cold record. We do not consider them.
   That decision covers two of plaintiffs’ arguments. They ar-
gued on appeal that their complaint gave the Bureau actual
knowledge that they were working without compensation;
they did not make that argument to the district court. They


     3The Bureau raised the waiver issue in its appellate briefing; in their
reply, plaintiffs asserted that the allegedly waived issues “were raised, of-
ten repeatedly, during the trial.” They did not cite the record to support
that claim, and our review of the record produced no support for it.
No. 16-1029                                                    15

also argued on appeal that the Bureau’s culture discouraged
compensation for all “not significant” overtime—short-dura-
tion work, work on administrative tasks, and work performed
from home. But in the district court, they argued only that the
Bureau discouraged compensation for work done on a Black-
Berry. They did qualify that argument, conceding that the Bu-
reau would compensate certain kinds of BlackBerry work, in-
cluding long stretches of work. But the broader argument that
all insignificant overtime was forbidden is new on appeal.
   C. Factual Errors?
    We turn to the factual arguments that are properly before
us. Plaintiffs argue that the district court got the facts of this
case wrong—that it clearly erred by holding that the Bureau
did not actually or constructively know they were underre-
porting their overtime or pressure them to do so.
     We reject these arguments. First, plaintiffs emphasize that
the Bureau knew they worked overtime on their BlackBerrys.
As we have explained, that point does not win the case. The
district court agreed that the Bureau knew about at least some
off-duty BlackBerry work. But it also found that the Bureau
did not know that such work was not being reported and
paid. Repeating the former point does not respond to the lat-
ter.
     Second, plaintiffs emphasize that their supervisors did not
tell them to submit slips for BlackBerry work. But supervisors
did not give those instructions for any particular type of work.
As the district court found, plaintiffs and other officers knew
the procedures for claiming overtime pay and used them
without regular reminders.
16                                                             No. 16-1029

    Third, plaintiffs point out that supervisors remembered
approving very few slips for BlackBerry work and that the Bu-
reau was not able to produce many slips submitted for that
work. True, but as the district court found, that was because
slips need not and usually did not say how work was done.
    Fourth, plaintiffs argue that the Bureau could and should
have cross-referenced slips that had been submitted against
either phone records or supervisors’ knowledge of overtime
to ensure that its employees were reporting their time cor-
rectly. Plaintiffs cite supervisors who said that they regularly
looked at slips and called plaintiffs’ proposal “possible.”
Those citations in plaintiffs’ appellate brief edit out contrary
testimony describing plaintiffs’ proposal as “burdensome”
and “an impossible task.”4 Given that testimony, the district


     4Elsewhere in their brief, plaintiffs selectively quote a former chief of
the Bureau. The witness explained that when he was non-exempt, he
sometimes would not submit overtime slips for short work sessions. He
was asked if that was how to get ahead in the Chicago Police Department.
Plaintiffs quote part of his reply, implying his answer was equivocal
agreement: “I think you get ahead by, if you want to—I think it’s just hard
work. And if that’s part of hard work in getting the job done, maybe.” But
his full reply was, “No, I don’t think so. I mean, I don’t think anyone—
honestly, I don’t think anyone really keeps that close a track of that. I think
you get ahead by, if you want to—I think it’s just hard work. And if that’s
part of hard work in getting the job done, maybe. But just the fact that, oh,
I worked overtime, didn’t put a slip in, there’s guys in these units, Detec-
tive Division and in Organized Crime, that have prolific amounts of over-
time, and they still get promoted and get ahead.” This court has cautioned
counsel to be conscientious when editing quotations to avoid giving the
appearance of trying to mislead the court. See Cleveland Hair Clinic, Inc. v.
Puig, 200 F.3d 1063, 1069 (7th Cir. 2000); United States v. Burrell, 963 F.2d
976, 983–84 (7th Cir. 1992); Duggan v. Board of Education of East Chicago
Heights, 818 F.2d 1291, 1297 n.14 (7th Cir. 1987).
No. 16-1029                                                     17

court reasonably found that plaintiffs’ proposal was “ex-
tremely impractical.”
     Finally, plaintiffs attempt to undercut the force or credibil-
ity of various evidence, pointing out, for example, that one
supervisor testified that her subordinate submitted slips for
phone calls but did not produce those slips, that another tes-
tified about a misdated slip and others submitted recently,
and that a third was not sure whether his subordinate’s off-
duty phone calls were made on his BlackBerry. Plaintiffs also
point out that the district court mistakenly implied that a par-
ticular person testified when in fact someone else testified
about him. This is not the stuff from which clear errors are
made. We do not sit to re-weigh the district court’s plausible
findings about credibility, much less the occasional scrivener’s
error. See TABFG, LLC v. Pfeil, 746 F.3d 820, 823 (7th Cir. 2014)
(clear error standard requires special deference to the district
court’s determinations of credibility); Fyrnetics (Hong Kong)
Ltd. v. Quantum Group, Inc., 293 F.3d 1023, 1028 (7th Cir. 2002)
(clear error standard does not permit reversal based on re-
weighing evidence), quoting Anderson v. Bessemer City, 470
U.S. 564, 573–74 (1985).
    We do not mean to imply that plaintiffs had no evidence
in their favor. As the district court found, “many plaintiffs
credibly testified that they did not submit” slips for off-duty
BlackBerry work. Some said that was because of the Bureau’s
culture or out of concern for their positions. One plaintiff, a
supervisor, told his subordinates that others might frown on
such slips. We are especially troubled by the 2010 General Or-
der and the accompanying compliance statement, which an-
nounced that employees “will not be compensated” for Black-
18                                                             No. 16-1029

Berry work except under certain circumstances. That lan-
guage appears to run flatly contrary to the Bureau’s FLSA ob-
ligations.5 The Bureau says that the order still permitted com-
pensation in most circumstances, but that argument is cold
comfort: the Bureau cannot refuse to compensate any of its
employees’ work. If the Bureau had won summary judgment,
or judgment as a matter of law, this appeal would present
very different issues.
     But having correctly proceeded to trial, the district court
was not obliged to resolve conflicts in the evidence in plain-
tiffs’ favor. And there were conflicts in the evidence. While
witnesses blamed the Bureau for their reluctance to submit
overtime slips, they could not point to anything the Bureau
did to cause that reluctance—not instructions, discipline, or
reprimands. Some officers did submit slips for BlackBerry
work, and the Bureau paid them.6 As for the General Orders,



     5 The trial testimony also reflected some employee confusion about
the circumstances in which they needed to submit slips. One can certainly
argue that an employer has not created a reasonable reporting system—
has not been reasonably diligent—if its employees do not know when to
use that system. See Craig, 823 F.3d at 390 (reversing summary judgment
for employer in part because it was “unclear whether Craig even knew
she was allowed to petition for overtime compensation at all”). But that
was not plaintiffs’ theory at trial, so the district court did not and we do
not draw any conclusions from that testimony.
     6 Plaintiffs explain this evidence with a more elaborate version of their

unwritten-policy theory. On this account, the Bureau’s unwritten policy
had (at least) two exceptions: it would pay for BlackBerry work so long as
the work session was long enough or the work was part of an “official
assignment” (an undefined term). At some point, elaborating a theory to
avoid bad facts looks like post hoc rationalization—the equivalent of Ptol-
emaians adopting epicycles to fit their geocentric theory to inconvenient
No. 16-1029                                                       19

the district court found that no plaintiff stopped submitting
slips and no supervisor refused to approve slips because of
them. Plaintiffs point to no contrary evidence on appeal. As
unfortunate as the Bureau’s phrasing was in the General Or-
der, we are not “left with the definite and firm conviction that
a mistake has been committed.” Furry v. United States, 712 F.3d
988, 992 (7th Cir. 2013) (defining clear error) (citation omitted).
   The judgment of the district court is AFFIRMED.




facts instead of adopting Copernican heliocentrism. The court was not
obliged to accept plaintiffs’ explanations.
