Comment by ta1243

These sites implementing this could also implement a DNS TXT record or similar saying they are over 18s only (gambling sites would be included here too, and with a little thought you can categorise the sites).

They could publish their IP addresses so that the traffic can be blackholed at the router by the account holder.

The choice would then be down to the person paying the bill whether to block or not.

It won't apply to shady sites, but those sites won't do age verification anyway.

The problem is nobody wants the account holder to have the power.