It sounds like you are assuming that the wallet needs to re-validate each session and I don’t see why this would be needed. Each user account would just need to validate their age once then the website operator could store this in their database. If you’ve validated once you can be sure the user keeps being old enough.
I believe something like this is supposed to be a use-case of the digital EU Wallet. A website is supposed to be able to receive an attestation of a users age without nessecarily getting any other information about the person.
https://en.wikipedia.org/wiki/EU_Digital_Identity_Wallet
Apparently the relevant feature is Electronic attestations of attributes (EAAs). I’m not really familiar with how it will be implemented though and I am a bit afraid of beurocratic design is going to fuck this up…
Imo something like this would be magnitudes better than the current reliance of video identification. Not only is it much more reliable, it will also not feel nearly as invasive as having to scan your face and hope the provider doesn’t save it somewhere.
Is this actually practically achievable or mostly theoretical in a lab? Is it confirmed that the cops have actually managed to do this?
The rules only matter if the admins adhere to them and enforces them consistently.