I have found a pattern in my "random" reboots. I'm I am playing a game with sound, first the return softkey will get slower and slower, and then the sound will go away. My natural instinct is to hit the volume control, and that's when it reboots. This is consistent and repeatable.
I think that it is possible that every reboot was when I changed the volume, playing a game or listening to music! I don't know if this is a cause or a symptom. More data would be good. I don't listen to music off the phone all that often (no input on my car radio).
Recovery: last time the sound vanished from my game, I closed the game & opened another game with noise. The sound came back. I closed that & opened my original game and it worked well. The phone did not reboot.
So, at least we have 1 consistent situation when it reboots - if we get enough data, maybe Motorolla or Android will fix it. Please?