Don’t get me wrong, I’m all for privacy. But between setting up the birthdate when creating my children’s local account on their computers, and having to send a copy of their ID to every platform under the sun, I’d easily chose the former.
I’d even agree to a simple protocol (HTTP X-Over-18 / X-Over-21 headers?) to that.
I’m not sure what you mean by “massive leak able tracking” in this case. It’s literally a flag that indicates the user’s age bracket, and means sites don’t use the really invassive options.
setting that flag involves the leakable process.