Tried this at work today when I was changing batteries in a nurse call system handset. Never thought in a million years it would work,,, but bloody hell it does. !!!!! ( I reckon as the battery get's low the metal on the base of the AA battery becomes convex (rather than flat when new), thus causing the bounce.
Nah I flatten the batteries with my toy helicopter. Our dog hates it, twice as much as our budgie now. So much so, that when I mention helicopter, he runs and hides.