Parents already have the ability to lock down Android or iOS devices for their own children, if they choose to do so.
That's just not true. If you give your kid WhatsApp access because that's how 95% of their peers text each other, then your kid has access to a hidden chat that can only be revealed by typing a secret code in the search bar. Tell me how a parent is supposed to parent their kid when they can do that? Locking down WhatsApp is no solution because then they can't talk to anyone. (Other countries do not use SMS as much as…
So the solution to parents deciding to give their kids access to stuff is to make me flash my ID every time I go online on one of my devices that I use in my childless household? And you're confident that there won't be plenty of parents who just put their ID information in for their kids anyhow?