Jason, if they are in employer provided accomodation, Qatar Airways being a case in point, there may be a house to house check, security guards reporting back to the employer etc.

Qatar Air is an extreme example. But do you think they are the only ones that do this? And if someone decides to dob them in (for whatever reason) that police won't investigate?

Depending on the employer/accomodation conditions - the possibility may be remote. But they should be aware of the risks they are running in order to make an informed decision.