I honestly don't know of a policy, per se, but it's probably something you do and don't mention to NPC-- those gray areas. Somehow, though, I think if anyone wants to swap these songs from Greek Chat, those are probably better left to private messaging
My chapter of initation has no drinking songs, but the chapter I advise does-- they are hysterical, but they never directly mention the sorority's name-- instead, they refer to violets, deltas, etc.
Regardless, there are some fun songs out there-- all the more reason to enjoy being a member of the BEST sorority!