Perhaps that sounds a little bizarre, but in fact, my Palm Tungsten E2 was automatically turning itself on. I would turn it off, and it would automatically start right up again after about 10 seconds. I thought this bizarre behavior was the result of a bug, so I did a hard reset. After syncing the Palm again, the behavior returned.
I investigated the issue on the Brighthand Forums, which is an very valuable resource for Palm users. According to this thread, it was an issue with a birthday setting this week. My sister-in-law’s birthday is January 7, so that was causing an alarm for 2006 (The default reminder for birthdays is 7 days). Since it is no longer 2006, apparently the alarm does not display, but the device still turns itself on. I changed the reminder for her birthday to 3 days, and all is now well. Beats the heck out of calling Palm tech support, since my warranty expired some time ago. In summary, if you have any event within the first week of January, you should set the reminder between January 1 and the day of the event, not December.