And I am going to restate how it’s an absolutely terrible idea, and will always fail with its perverse incentives. This does not solve any problems and creates many more.

Your idea will create a massive black market for “adult validation tokens”, handing billions of dollars to criminal groups reselling these things.

And then where such a system goes in 5-10y. Sure it’s sorta anonymous today, but then new government decides - “let’s make it mandatory to be sold with a binding identity and credit card.” Suddenly you need that token to log in to any public website. And Chinese, European and American authorities demand realtime access to the global logs.

Every censorship system you build, even if it seems “good”, will eventually censor you and the things you care about. Don't design or build oppression technology.

The very idea that you can realistically enforce Point of Sales age checks at scale is not sensible.