that kills two birds with one stone, you can then show everywhere online you are human and how old you are without the services needing any personal information about you, and the sellers don't know what you use that id tag for.
In fact, even if you can ban the human for life, I'm not sure it solves anything. There are billions of people out there and there's money to be made by monetizing attention. AI-generated content is a way to do that, so there's plenty of takers who don't mind the risk of getting booted from some platform once in a blue moon if it makes them $5k/month without requiring any effort or skill.
That might make it less likely someone would ever sell it because to get a new one might take a very long "cool-down" time and it'd severely hamper the seller.