Renaming tricks isn't suable because tricks aren't copyrighted or patented (with the exception of a few stage illusions). However, renaming plays definitely is suable since scripts are very solidly protected by law (similar to written stories, formats of TV shows and characters), but I doubt people would sue schools for that.. unless it's a huge school and there is a lot of profit made but usually that isn't the case. It would cost more money to sue schools for their musicals than what you could possibly get out of it.
However, this isn't about laws, this is about ethics and I don't see anything bad about performing tricks you have been able to figure out from trailers apart from the trailers themselves allowing you to figure out those tricks.