I agree, those mixed martial arts guys are pretty amazing and I'd hate to be in a fight with one of them, or anyone for that matter. But most street fights aren't just you and some guy. Its you and 5 guys who want your wallet and they're usually armed with something. Training for instances like that is great, but avoiding them at all costs should be the priority #1. And it might be a good idea to have the business card of a good lawyer, cause if you "win" and the police come, you just might be arrested and charged. Again, I'm just going by the incidents I was unfortunate enough to witness here (from a distance thank goodness). By all means always defend yourself, but you'd be surprised how quickly a simple street fight becomes a lawsuit frenzy. Of course it all depends on where you live.