Son able to disable his watched profile

I notice that my son created a new account on his Vista PC and is able to bypass the monitoring tool. He claims he just says no do not monitor this PC. I can go in to his profile settings online through your tool and check the box for the new profile, but he is able to keep turning it off. How can he do this without my userid and password?

I notice that my son created a new account on his Vista PC and is able to bypass the monitoring tool. He claims he just says no do not monitor this PC. I can go in to his profile settings online through your tool and check the box for the new profile, but he is able to keep turning it off. How can he do this without my userid and password?