A very unpleasant thought , and I am not sure of the chemistry and physics involved but bringing one of these devices aboard an airliner is essentially bringing and incendiary device on board, whether the otherwise harmless device randomly decides to cook off on its own or not are they not a risk in the event the bad guys find a way of making sure they do go into thermal.
obviously you would need some form of complex manipulation of the battery and its its power output needing a computer to manage , but then they are encased in a computer anyway. Seem very scary to me and I have to say i am not sure they belong on an aircraft if penknives, bottles of water and tubes of toothpaste are all banned.