I can agree that if we give the parents the opportunity
Please, get away from that non-NPOV "parents who want their children not to see .." assumption. If we build filters, they should be applicable for any purpose whatsoever, be it parents->children or Chinese elite->Chinese citizens.
Propose a scheme that allows this, can be kept reasonably clean and implemented in an easy to use fashion, and I'll look at it. Alternatively, root for my team certification proposal, because it allows just that.
Regards,
Erik