Contacting police? Ridiculous. If it wasn’t a for profit scheme, but is against policy, take the pool and issue a warning that the next time it happens more drastic action will be taken. End of story.
In my supervisory position, there's a lot of stuff I don't know, cause if I knew, I'd have to do something about it. I use rules only when people don't act like real, live adults. However, when someone brings something to your attention, there's no longer any plausible deniability, and you have to follow the rules. Everything's against the rules, and you'd go crazy trying to actually enforce all of them.
BTW, my ignoring rules does not include theft or something actually damaging, just the nonsensical little stuff that doesn't make any difference.