[stavros]

It might be Fort Knox just fine at some point, when computers will require a cryptographically signed government certificate that you're over 18, and you can't use the computer until you provide it.

[AnthonyMouse]

Even in that case the large majority of the population would then have that certificate and the motivated minors would just beg, borrow or steal one.

[voakbasda]

No one has ever faked a government ID?

[stavros]

Nope, not a zero-knowledge proof with cryptographic signatures.