I don't think it was news when the Who played Cedar Falls, and one after another was carried out on a stretcher. That was far and away the worst I've ever seen.
It was news, however, when they played the Riverfront in Cincinnati in 1979 and eleven were killed. Not the fault of The Who, though. More the fault of the concert promoter and the arena staff who were not in proper control of the crowd waiting to get in.
But yeah, I remember when they opened "The Summit" arena in Houston and they would have television cameras panning through the crowd between sets, putting the video up on the big screens at the ends of the place. There would be all kinds of bad behavior on display from people consuming drugs and alcohol to girls going topless. Those were the days. And before that I remember when Led Zepplin came to the Coliseum and the crowd actually got so nuts that they ripped several rows of seats out of the concrete floor. I remember drug dealing going on just about everywhere. I remember people lined up to use the bathrooms and using the sinks as urinals. I remember people throwing up, quite violently, in the stairwells. I most certainly remember the police arresting people outside the venues...like shooting fish in a barrel.
I also remember being genuinely surprised at the contrast in fan behavior between every other band and The Grateful Dead. Of course there were quite a few people who were zonked out of their minds on acid but the overwhelming attitude at those shows was one of profound peacefulness, politeness and respect for others. People would actually say, "excuse me" when they bumped into you. Kind of weird.