> There is a problem with schemes like that.

/goes on to discuss how government legislation of specific schemes is the issue, not the schemes themselves.

Then we don't legislate specific schemes? The GDPR doesn't do that, for instance, it spells out responsibilities and penalties but doesn't say "Though shalt use this specific algorithm".

Remember, this discussion started with a call to ban all age checks, which itself is a government action and restriction on the agency of private business.

There are ways that private entities can implement age checks both securely and without leaking much other information, so it seems very heavy-handed to ban them. Private entities are building such systems between themselves already, without government mandates on the specifics.