I saw Joe Cocker in about '76 and he was legless. I actually felt pity for him. He couldn't do anything right, had no vocal range, no power in his voice. But he was pissed when he came on stage and continued to drink through the show.

Most of the live music I see now is in clubs and most of the performers have an ever present pint. I have heard some wonderful performances, but I think that a performer would have to literally swill beer or get on to the harder drinks to get intoxicated at a gig. Usually it's a five minute song, a quick sip, another five minute song etc. I really can't remember the last time I've seen a performer in a state that I would consider drinking to excess and ruining their performance.