I use it to (1) Lock me out of my laptop at 10pm (2) Prevent me from changing my dns from OpenDNS-family filter. (3) Save the passwords for parental controls apps in a file readable by root only so that I can't access them at whim.
It is still a prototype, but I believe it is full proof. I don't know a lot about user/group mechanism in Mac/Unix, so I am trying to find someone who does. The aim would be to have an abmindicate like tool (http://www.pluckeye.net/abmindicate.html) for Mac/Linux users.