I wouldn't say every browser, but the correct place for the policy is on the device of the parent who is demanding the special feature. Sites' obligations should be limited to basic disclosure of "this site might contain X" metadata.
Benefits:
1. Orwellian abuse: No creepy-ass super-abuseable government panopticon knowing every goddamn service you've ever made an account on, with the ability to arbitrarily revoke them and/or block new ones.
2. Costs: The majority of the costs of creating and maintaining the system fall upon the people who actually use it and want it to exist, rather than a bunch of other adults across the globe.
3. Parent focus: Most enforcement exists in a physical realm where parents/guardians at least have a chance of understanding, monitoring, and managing it. "Little Timmy is using Daddy's phone" can be determined instantly at a glance.
4. Exceptions: If the child has some health-class homework and can't access the right Wikipedia pages anymore, the parent can easily grant exceptions and revoke them.
5. If someone's religion says that unclad ankles are smut, then their church can create their own site-rating-site and adherents configure their family's devices to it.
Benefits:
1. Orwellian abuse: No creepy-ass super-abuseable government panopticon knowing every goddamn service you've ever made an account on, with the ability to arbitrarily revoke them and/or block new ones.
2. Costs: The majority of the costs of creating and maintaining the system fall upon the people who actually use it and want it to exist, rather than a bunch of other adults across the globe.
3. Parent focus: Most enforcement exists in a physical realm where parents/guardians at least have a chance of understanding, monitoring, and managing it. "Little Timmy is using Daddy's phone" can be determined instantly at a glance.
4. Exceptions: If the child has some health-class homework and can't access the right Wikipedia pages anymore, the parent can easily grant exceptions and revoke them.
5. If someone's religion says that unclad ankles are smut, then their church can create their own site-rating-site and adherents configure their family's devices to it.