LiIon batteries will get very hot if they are short-circuited. Exploding isn't a big surprise.
But the gagging order - that's a different matter. Don't like that.
I'm going off Apple stuff. I have an iPod, and use it on journeys. It's supposed to go something like 16 hours on a charge. I'm very lucky to get 4 hours - and always have been. Apparently, I listen to the wrong kind of music - quiet, gentle stuff.
If the battery in there could be removed/replaced, like the batteries in my camera, telephone, and all the other kit I use, I wouldn't mind. Instead, I carry a battery pack with an Apple connector (they couldn't even use mini-USB!)