The question is whether parents should bear this responsibility or the state.
But what I'm actually questioning in my comment above is effectiveness of the technology solution proposed at the device level.
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.