This morning when I got out of class I found someone had undone several of the velcro straps that hold my electric bicycle's battery on. Fortunately the battery (and the bicycle!) were still ok.
My guess is someone just saw a bulky black bag and decided to steal it without knowing what was inside. Walk-by snatch and grab. I like to think the sheer weight of 30 lbs of lead acid batteries scared them into letting go of it. And anyway there's more straps holding that thing down on the front side.