this happens at times to me and I've just chalked it up to the fact that I'm booting from sd. I really don't have any evidence, but perhaps I need a better SD. Still, it seems to happen when I'm unable to plug it in. Not that it knows that I'm unable, but I'll go weeks without a crash, and then when I'm traveling and need to conserve battery, poof, I get a random reboot. Annoying.

Also, I only use browser and feedcircuit--never email apps--and this happens.