No one has brought this up, but changing any part of the show (even a word here or a line there) is against the rules--not to mention the law--and could result in the show closing down.

I know that theaters and high schools change things every day, but I also know of a few unfortunate cases where MTI employees or others were present and forced them to change it back or close down.

I know there are those who would argue, "Why shouldn't we just change that one curse word to that one milder one so we can do this wonderful show?"
Respecting the author's intent IS a big deal and gets stomped on all too often (hence the laws about not changing anything).

Besides, as far as "conservative parents" or whoever complaining, they'd probably be more horrified by Paul's confessional monologue than the mention of "tits and ass" (which can be heard on shows like Will & Grace or Friends).
15-year-olds know ALL the curses. The ones involved in theater are often the least likely to throw them around just for fun. (Once they're given permission to swear in acting class, it can lose its thrill for them.)

If you're trying to protect your student population or parent population or community or what-have-you, then put a disclaimer on the poster ("not suitable for children under 13") or DON'T DO THE SHOW. Simple.

Otherwise we'll have "Les Miz: The Happy Edition" where no one dies because it's too traumatizing for the students, or "Cabaret" (which high schools do often in quite racy ways) being changed so that the Nazis are just "really grumpy guys" and the saucy dance numbers are replaced by good ol' wholesome square dancing.