I fully agree with the last part. That's what mkruer said in an earlier post, and filled my heart with relief, namely that if someone becomes a serious problem, he'd kick him. That's the kind of thing we all need to understand. But if you have a written rule that such and so has final say, inevitably some otherwise genuine discussion will be shortcut by some appeal to authority. That's what I would REALLY not like to see happen. Now, like I said, I do believe there has to be 'final say' rules, as a weapon of last resort, but be kept hush, for the reason stated above. And the purpose of having the final say attributions would be as a final buffer before mkruer's boot kicks into action. Additionally, I'd make it a rule of decor, that nobody who has 'final say' on any matter, should ever say so to anyone. When someone new needs to be told he or she is going beyond reasonable argumental style or boundaries, I submit it should be someone else's job to PM them to say "My friend, this guy you're calling an asshole is the one who makes final descisions in your subject of argument; tone it down for your own good."
Is this much to ask? So, for example, if an artist contributes a model and you tell him "look at this picture of the original, see? those engines are twice the size", and the artist will probably be convinced. If not, you could try and explain it in some other way. If he's still not convinced, you try a third way. In the one in a million case you don't get anywhere, you PM me and say to me, Daniel, I can't handle this guy.." So, I say to you "hold it, let me talk to him", and I PM him a message you'll never know what I said, and now he's all polite and nice and submissive...
Same goes if somebody in audio won't shut up; I might ask you for help.