Deep Purple Knebworth 1985: the sky went black with a rainstorm of bottles of piss. You cannot go the the toilets from the centre of a crowd of 120,000 in a field. So you piss in your empty bottles. Once you are soaked in piss (like getting caught in the rain in the open without a coat and soaked) it actually doesn't matter anymore.
Stranglers, Southampton Gaumont 1982 - support act bottled off the stage, seats ripped up and destroyed and thrown at the stage and at the army of bouncers. Loads of other similar gigs there in the early 80s.
It was all part of the experience and everyone, consenting fans and performers alike knew the score and willingly attended. Fantastic fun.