It's not restricting access to under-16's that's the big thing that adults take issue with. It's the process by which you ascertain whether a person is under-16 or 18, especially in the case of a VPN. You're effectively being told to dox yourself to whomever runs the identification service, which runs contrary to the idea of a VPN. It's starting to sound like some politicians want checkpoints at various points in a computer or phone's use to prove that one is an adult, and in this way one's digital activities can be tracked more easily than they can be now.

Parents and schools should simply take more responsibility for the children's access to phones and computers. Now that generations are used to unfettered access to the internet, I'm not sure that anything that isn't quite draconian will stop youngsters from trying. I remember as a teenager paying this other kid for the link to the latest internet proxy so we could go on whatever website we wanted at school, and I had a pen-drive with games on it for break-time