I took my fully-charged iPAQ 4700 to the office today and used a
Bluetooth connection to my mobile phone to pick up overnight email
en-route. I switched off the iPAQ once I'd finished, but omitted to
turn off Bluetooth. When I came to take my PDA out to use, a few hours
later, I found that (a) it was really warm, (b) it wouldn't switch on
without a soft reset and (c) that the battery life had gone down to
28%. Once I'd managed to get it to wake up again and I turned off
Bluetooth, it cooled down and it's since been fine.

Has anyone else seen this problem?

I suspect it's happened because I had email synch set up to happen
every 5 minutes during working hours (an ActiveSync setting) and I
presume, having had this experience, that the PDA wakes up even when
switched off and does this. I've just changed this sync setting to
"Manual" so hopefully even if I leave Bluetooth (or WiFi for that
matter) enabled, I shouldn't get the problem.

Would be interested to hear others experiences.