They can have sex in front of an audience of adults? Ok, that is a bit more open than I would like.
Can they masturbate in front of audiences as well? Again, call me a prude, but I think that is a bit over the top.
And you are missing my main point. Right, wrong, indifferent is irrelevant. If they want to control it, then it should be handled by the individual school districts.
EDIT: So, once past 16 years of age, there is no such law regarding lewd behaviour or the public display of sex in Europe? Not to generalize all Europe in one basket, but more of a general question.