Well, I know that the teachers at my school have gotten wise to BPM, so I just switched icons. It would be nice to have a locking feature and a switch the tooltip option, but not a huge priority right now. The teachers still haven't figured out the hide system tray icons option in Windows XP.
How about being able to password BPM, so like Instant Lock, only IL doesn't stop MSN being obvious.
Also, BPM sometimes kills my PC. If I lock it, about one time out of ten it'll my PC'll start dying. Check my process list, MSNMSGR.EXE using 98% CPU resources. XP Professional, done it on both SP1 and SP2-RC.
BPM also doesn't work sometimes. I try going into it and it won't go. If I go to the menu and tell it to lock it says that I have to exit Messenger and login again. This is incredibly annoying, esspecially when I REALLY need to use BPM.