Make unrestricted devices like alcohol: you need ID to buy (but the box containing the device you’re sold is indistinguishable from any other, so the device may have a UUID but it can’t be traced to your ID); kids caught with unrestricted devices in school have them confiscated; maybe fine parents, but I think discouragement and banning in schools is enough. Kids can have restricted devices, distinguished from unrestricted by appearance in a way that’s hard to fake.