Interesting point actually.. it doesn't say anywhere that the stripper was called in by the police, surely she's guilty of something or other - exposing herself to minors?
Plus, they must have very negligent teachers if they just let some random woman take her clothes off in the middle of a lesson.
And.. if this really was a request by parents, wouldn't the stripping company be a bit bemused by a customer asking for a stripper to sing a song - and also presumably the parents would have said "hi, we'd like to book an act for our son's 16th birthday? - yeah sure, it's at a secondary school. - costume? yeah why not come as a policewoman"