It's not really a huge bug, but, whenever you're invited to a tribe you can delete the text and write whatever you want instead of it.
http://gyazo.com/611e5971567a9064af7e1aaff9ad9e4f

Edit: I guess it's for every type of message like that.
Tribe creation: http://gyazo.com/ac2b04d11e81469d88e58574b091583f

yep
not just being invited too
when the inviter either gets rejected or accepted they get that pop up saying the person decline or accepted, that can be editted that too

edit: when unfriending a person too

some 1 said this when they were talking to me about a tribe they entered in: -he didnt tell me who invited him but this is all i can say- blah blah is asking you to join the tribe booty scratchers! -he changed it and he didnt tell me wut the real tribe name was- >_>

marriage thingy affects it too

Useful!