[hellojesus]

It's effective insofar as the parents secure the device. If it's a general purpose computer, and the parent forgets to lock the bios, kids will just live boot into Ubuntu or some other OS and do as they please.

Or they may install keyloggers (including hardware loggers) to get the parents' password and then go update their account.

Certainly this may help hinder them, but it won't take long for them to learn the basics of curcumvention, and the cost is regulated speech for OS manufacturers.