We did a gig once with a band we'd never met before, we got there to set up and I saw a very very nice lakland on a stand, once we'd set up a guy from the other band came in, we all shook hands and so on, and I asked him if it was his bass, he said yea so I asked him if I could have a play and he said yea, and then he said he was going to meet some people and left.
So I was sat on the drum riser noodling on this very nice lakland jazz, when 2 other guys come in, all of a sudden I hear: "WHAT THE F*** ARE YOU DOING? DO YOU HAVE ANY IDEA HOW MUCH THAT THING COST?!?!?!" After a little more shouting this guy said he was the bassist and was very annoyed I was playing his expensive lakland, very confused and apologetic I explained that the other guy said it was his. Turned out the other guy was the singer and they'd had a massive falling out over a girl, and the singer was trying to piss him off. The bassist was actually pretty cool about it, he realised I knew what I was doing and apologised for shouting. When the singer came back in grinning they kicked him out of the band and did an instrumental set.