I just can't imagine a situation that would cause me to riot. Seriously, it's a goddam hockey game.
More on topic: I always thought hockey fights are a lot more uncivilized and brutal than MMA fights.
Actually the majority of hockey fights are a joke. Even for pros, fighting on skates is hard, 90% of the time two guys grab on, wrestle around for a few seconds, throw maybe 1-2 punches each, which don't land, or land in any meaningful way, and then the refs step in.
That is the reason I would be happy to see fighting out of hockey. Not because I don't like fighting, but I like good fighting, like.....MMA.
If I want to watch fighting, I'll watch professionals fight, if I want to watch hockey, I want to see hockey, not some crappy imitation of fighting.
There are some very good tilts in hockey, but they are extremely rare.