Update: Still the same issue. It's beginning to really annoy me. sometimes it will reboot itself 2 or 3 times during a one-hour meeting...without ever hitting a single button on it at any point. Then it won't do the mystery reboot for a week.
Also, it's getting glitchy with Google Maps...slows right down and then freezes. Obviously with a wifi-only device, once you have the "directions" and "navigation" locked in (on wifi)- having to reboot the device once you're off the wifi (and on your trip)- kills all navigation...so this really stinks.
All in all, I'm feeling like this device is starting to get pretty tired.