Your Kinks story reminded me that I once saw Ray Davies punch Dave Davies on-stage. It was at the Capitol Theater In Passaic NJ during (I believe) the Schoolboys in Disgrace tour. The Kinks were at a low point and there were a few hundred folks in a room that sat a few thousand (IIRC). The band wasn't happy (I assume) about the sparse crowd and you could hear the brothers woofing at each other between songs. After the first encore, as they were walking off, Dave elbowed Ray in the ribs and Ray clocked him.
They didn't come back out.
The crowd was definitely a bit out of control at that one.