It would be not very reliable because kids could take parents' card under some excuse (I want to ride an electric scooter, they allow only adult users so I need a card).
I'm not an expert but it would be helpful to look into the similar field of gambling. I read that there's lots of teenagers that are gambling and presumably they would evade controls in the same way, use parent's credit card or get them to fund a wallet of sorts. And maybe steal their parent's ID and use that for verification.
High tech verification that requires the ID to be photographed along with a facial verification largely solve this problem I believe, but I imagine kids go to gambling sites that are either unregulated or loosely regulated in some sketchy jurisdiction (which can be accessed with VPNs even if banned in a country.
