For Mac OS 10.4, why do the parental controls on internet surfing always reset when I start up?

I set parental controls on the internet on one user's account. But after a while, when I go and check the status, instead of seeing ';Managed';, it is always back at ';Standard'; (free access to all internet). Is there a way where I don't have to reset the controls every day?For Mac OS 10.4, why do the parental controls on internet surfing always reset when I start up?
I assume the user is an admin user and thus has the power to set things back they way he/she likes it. Why don't you setup their account as a non-admin user? That should take the controls out of their hands.