I have not had any issues with LiPo or LiIon batteries and have abused more than my share of them. I have dropped them >100' onto asphalt, run them full tilt into the shed at the field, Hit ghost branches, hit fence posts, discharged them at rates greater than spec, run them down to cutoff/brownout. I have seen what "can happen" plenty of times at FliteFest during combat.
They do not just spontaneously combust without reason or just short out. If they are physically damaged, discharged at extremely high rates, or charged at rates greater than design spec, sure, they can ignite.
If you have one that is damaged, discharge it fully and don't use it any more. (except maybe in combat or a plane you hate)