I also worry about an over heating battery. Can they can melt, blow, cause irreparable damage? What will they say if one heats to the point of damage? Oh, well, sorry, but you should have turned it off via the power/volume buttons when it first showed signs of warmth.
Until they release concrete warranty info, I'll remain leary of any and all non-replaceable battery types. Mainly because of their skills at skirting a valid question.