The power off bug on the iPad is even worse than I thought. It happened again last night, when the battery died while I was sleeping. What really irritates me about it is that I had quit the game entirely before going to sleep. Not sure where that leaves things, as far as who is driving the bug.
It's very frustrating, though, as I'm playing hugely better on the iPad than on the iPhone, of late (not sure why, but my average distance per game is close to double). My record longest is also significantly longer (8900 vs 6800, IIRC), but my longest distance in a single run of a vehicle is longer on the iPhone for five of the six vehicles.