Didn't see any raised tempers at all, only heard of one drunk.
Great group of people there.
A special <S> to NB & SB for making it possible!
Some of it I added to the superfokker thread.
I'd expect to see a WWI arena shortly (2 weeks x2)

Not too long after that I'd be watching for player configurable arena's to show up.
HTC hosts them, you set the map, planeset, etc. There was no firm number talked about for how many could fly in one, but by the sound of it you would have no problem having a 8vs8 squad duel in one. With good potential for even more than that.
Terrains would have to be submitted and approved much like skins are.