> Some people want to require device attestation, so you could only do this handshake from a government approved device running a government approved operating system. Forget using Linux or maybe even a general purpose computer at all.

The reason this is a non-problem for the purpose being discussed (age verification on social media) is that you can simply allow anyone with a de-Googled phone or using Linux on a laptop (or even Mac or Windows) to bypass the age check. You don't need a 100.0% accuracy solution, anything above 90% is fine.

Essentially all teenagers are using social media on Android or iOS with apps from the official app store. If you make social media unavailable only on those devices, they are not going to be switching en masse to SailfishOS or start to carry around backpacks with laptops.

Maybe a few will. But then they're going to be very lonely on their social media and subsequently stop caring.