Back in 1994, the Mighty Mighty Bosstones played with Wax and Face to Face at WUST (now of course the 9:30) and there was no barricade. They were letting kids jump up on stage and do their thing and at ANY given point there were 2 to 6 people diving off the stage. I really couldn't get over how insane it was, but for the most part people were being cool about it and I didn't see any major injuries.
Then of course there was the Jesus and Mary Chain on Halloween, that same year. The older short guy with the moustache and belly (you all know the one...happy guy who always seemed drunk and would show up, jump around with his hands in the air, etc.) was body surfing and then all of a sudden people tossed him up. He flew up and there was nobody to catch him...so he landed on his head (at least from where I was standing that is how it appeared). It caused a flurry of snickers though, that's for sure.