Twice? I would have said that it's something that most normal people learn their lesson from the first time. Cheesy
After the first time I put a floor stand next to my amp and vowed never to put my guitar on the wall hook unless the lead was unplugged but 3 years later on the one occasion that I disobeyed my oath, physics came to give me a painful reminder. Ah well sh*t happens, she still plays beautifully although I am going to reassess my intonation next time I change strings.