Even better, make the flags granular: <recommended age>, <content flag>, <source>, <type>
13+, profane language, user, text
17+, violence, self, video
18+, unmoderated content, user, text
13+, drug themes, self, audio
and so on...
ASACP/RTA https://en.wikipedia.org/wiki/Association_of_Sites_Advocatin...
PICS https://en.wikipedia.org/wiki/Platform_for_Internet_Content_...
POWDER https://en.wikipedia.org/wiki/Protocol_for_Web_Description_R...
Tools avaliable for decades.
But as said multiple times, the childs are the distraction, the targets are privacy and freedom.
ASACP/RTA https://en.wikipedia.org/wiki/Association_of_Sites_Advocatin...
PICS https://en.wikipedia.org/wiki/Platform_for_Internet_Content_...
POWDER https://en.wikipedia.org/wiki/Protocol_for_Web_Description_R...
Second, all ISPs could offer in their basic service something like DNS4EU modes, just like they offered email and web space decades ago (optional, nobody was forced to use them).
DNS4EU https://en.wikipedia.org/wiki/DNS4EU#Public_resolver
Parents would only need to configure the account to "child". Laws could force companies to properly tag their pages and sites. And privacy would be preserved.
Instead we have to keep on fighting the Crypto Wars. The childs are just a decoy, the target is destroying basic rights.
Clipper chip war, eg. https://en.wikipedia.org/wiki/Clipper_chip#Backlash