Not anything beyond How to contribute to the world
With “required” guidelines, I guess you mean for public areas. Beyond that, I think it is up to the area owner/builder to ensure certain standards. But global suggestions sounds like a good thing!
Oh, that would actually be quite handy. You would always know what “out” is.
I think, maybe these sort of guidelines should exist in the help/popup tips inside the game, to be more accessible?
/Accipiter