They've already done it, mate. You can go read about the Australian law. They are putting the burden of proof on the tech companies: "You have heaps of data on

They've already done it, mate. You can go read about the Australian law. They are putting the burden of proof on the tech companies: "You have heaps of data on your users, you know who are young teens because you target them for marketing. Ban underage kids or we fine you."