In every OS I know of including linux, you need admin/su rights to create a user account. If the age is tied to the account that at least prevents tampering without admin/su access.

I suspect something the nonprivileged user can effortlessly change would be deemed insufficient. :P

The way this is written, it would just be a case of entering your age or DOB at account creation, which wouldn’t be so bad. Indeed, this would be the kind of parent-empowering solution I’d like to see, since it kind of assumes the admin of a device (who sets up user accounts) is an adult who will enter the correct info for their kids.

Of course, there’s always the concern they might try to push for adding 3rd party age attestation after the fact, with this being the thin end of the wedge. And it’d be a bit of a pain for the various linux distros to organise a compliant solution even IF it’s just adding a new parameter to useradd and the associated “age signal” API for applications to query.