I've only ever had to dispose of one LiPo in the 5 years or so I've been racing and that was because a crappy Novak ESC went bad and tried to take the battery with it. I've run cracked-case 4S in an 1/8 scale buggy all summer long, various other off road and on road scenarios, and I've never had a battery go bad. I'm going with operator error or you're buying crap batteries.