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.
On the one hand, it is a privacy nightmare.
On the other hand, those laws are so badly written, they will apply to things you would never consider an issue. E.g. a security camera, a router, a NAS. For each of them, the law applies, because they have an OS, they are attached to a network, and they have logins. Think about it, and it basically applies to any network enabled device.