a) I don't think there is any European plug that can be forced into a NEMA outlet, the pins are just spaced too far apart to make that work even using brute force. NEMA 1-15 has the rongs spaced 13mm (give or take a few tenths) apart, all round pin varieties 19mm on centre, BS 1363 22.5 mm. So... an adaptor (purchased or makeshift) must have been involved.
b) could have been a portable DVD player I guess - they look a bit like those Nintendo DS GameBoy successors. Don't knopw if they have video out to connect to a TV though.
c) qhile being a bit more expensive, code-free DVD players that happily play any DVD are readily available.
With a bunch of bored kids involved, taking a pile of DVDs kind of makes sense. It would be far more interesting how the accident happened. We aren't likely to ever find it out I guess. Undervoltage is probably the least likely explanation - I mean we're talking about electronics, not big motors!
