Infosecurity isn't really sure either, but the breathtakingly simple technology tweak appears to have been coded as a backdoor to Windows XP for administrators who are having password difficulties.
I'm surprise with Infosecurity Magazine post on "TuCows review shows how to start WinXP without a password" after watching the video on Butterscotch tutorial. This isn't a hidden command in XP. Anyone can simply issue the command and do so (with administrator priviledge).
control userpasswords2