Hmm, why don't the parents just stop them getting the game in the first place? Mature games are usualy 18 anyway so they would need their parents to get it for them in the first place.
I got it from a sign site. Let me get the link for ya BRB.
Edit> Well it figures. When I dropped AOL I save just a few of the links I had. Figures the one I wanted to post is one I didn't save. If I stumble on it I get it to ya.