Haven't seen any violence either, but I saw a minor spat on a CO ERJ a couple of years ago.

Self-important and nattily-dressed middle aged man boards, removes his jacket, folds it lengthwise and carefully places it in the overhead, taking up the entire length of the bin. He then, of course, closes the bin. It's a full flight, though, and a casually dressed younger man opens the bin, flips the top half of the jacket over the bottom half and tosses his carryon in.

Sharp dresser goes apoplectic, stands, and yells "Hey, what are you doing? That's my jacket!" Mr. Casual turns and says, er, casually, "So get yer own f**king plane."

Natty makes a big show of refolding and replacing his jacket in the bin, all the while staring daggers at the glib newcomer