Even better, the site could just tell the browser that there's age-sensitive content and the browser could check it. There are already standards for this!
The problem is, it doesn't give a legally-enforced monopoly to any rent seeking data brokers, and it doesn't act as a foot in the door for requiring government-ID attribution of all internet activity everywhere.
The problem is, it doesn't give a legally-enforced monopoly to any rent seeking data brokers, and it doesn't act as a foot in the door for requiring government-ID attribution of all internet activity everywhere.