In the course of setting up CyanogenMod 7.2 on my T-Mobile G2 (also known as the HTC Desire Z), I installed ClockworkMod Touch Recovery. My usual practice before that was to power off my phone and plug it in to a USB cable, attached to a wall socket, for recharging. However, with ClockworkMod Touch, trying to do this results in the phone always booting to the recovery mode, whether I plug in the cable before or after shutting off the phone.
This is a nuisance; in effect, I have to leave my phone powered on at all times, and turn off the sound when I'm sleeping. I suppose I could just leave it at the Recovery menu, but leaving the phone at a menu where two accidental touches to the screen could wipe the phone seems like a bad idea.
If I recall correctly, I initially had an earlier version of ClockworkMod Recovery installed, which had a menu option for powering off the phone. I only had that version installed briefly.