Check this out: apparently there's a keyboard now that will log you off the moment you physically leave your keyboard. Convenient or just whack? Link: http://www.gizmag.com/ksi-sonarlocid-auto-locking-keyboard/17934/
Whack if you ask me. I step away from my PC like 200 times a day to check faxes, copy, check files, scan, take a pizz, ect. Mostly 20' or less away. That's a lot of logging in and out.
