I think your objection regarding future governments is valid. The others I don't think are valid. For the record I agree with your conclusion that any effort like this is doomed to fail. But we already enforce point of sale age checks at scale across multiple domains. And as for perverse incentives, part of the proposal is more or less identical to how scratch cards for gambling work. There probably is a black market for these and there probably have been attempts at fraud. But they aren't very large, not enough to tank the system anyway.