Yes, that's how parental filters already work. They use a combination of rta tags and external data to block pages. Even works with Google safe search, firewall devices, etc. The rta ecosystem is already built out and viable.
I think the better tack is to stop acting like these laws are being pushed by honest actors with good faith intentions of protecting children.
I think the better tack is to stop acting like these laws are being pushed by honest actors with good faith intentions of protecting children.