@LukefromDC : it won't be that bad (it will be bad, but in a different way).
ANY website may ask a user to confirm they are 18+ (or whatever age).
There will be a huge amount of AitM (Attacker in the Middle) websites where naive people will be lured to (using fake emails, SMS, chat app messages or falsified QR-codes) and asked to confirm their age.
That AitM website will subsequently obtain a "ticket" (session cookie) from a real "relying party" website (with a potentially very different type of content than the victim is told).
Those "tickets" will be sold (or traded for watching ads and/or paying with privacy).
Reliable authentication requires a trustworthy identity verifier (even if identification is restricted to age+).