Interesting timing on this. Not that it was anything of this magnitude, but it just so happens I broke up a brawl during a Pat Metheny concert last night (boy, that sounds weird). At one point during the music while everyone was standing, the guy beside me and three guys behind me got into a fight. At first they were just cussing each other out, and I didn't think they were serious, just annoying. Then, the guy next to me pushes one of the other guys into the next row, and a bunch of shoving ensues. I was pushed a bit and narrowly missed an elbow to the face.
Now, I'm not particularly intimidating, but nobody messes with Deety's concert experience. Luckily I didn't have to beat anyone up (:p), but I did stand up, put on my death glare and demon voice, and tell them to SIT DOWN AND SHUT UP. The one guy left, and I stared down the other ones until they not only sat down but fell silent. It was actually quite fun.