I never had anything quite that bad. One time we were playing in a national guard armory and the power came from 100 yards away. My B3 was a half step flat.
Another time we were playing this bar and a couple bikers got chairs and put them about 5' away from the band, staring at us. They had a bottle of vodka they snuck in and were trying to drink it on the sly, which wasn't working. Finally one of them stood up and got about a foot away from our guitar player while we're playing Linus and Lucy, and says "you play like a pussy". Finally our sound guy, who might have been 140lbs, went up to them and asked them to move, and they actually did. To this day when I see that guitar player I tell him he plays like a pussy and we have a good laugh. He's a phenomenal player- won Galax, plays guitar, mandolin, banjo, violin, etc.