Part of being a parent is saying no when your children pester you for something you know is bad for them.

Did you read my comment? The issue is not being able to say 'no'. The issue is basically Sophie's choice: it's saying 'no' but then your kind misses out on a lot of social interactions with their peers vs. saying 'yes', but then your kid has a risk of getting addicted to this crap.

Missing out on social interactions weighs heavily on kids too.

Making everything harder is that even primary schools sometimes allow kids to play kids to play Roblox or use ChatGPT. For parents it's an uphill battle if even their role models think it's fine to play addictive games or make Tik Tok videos. We picked plenty of battles of not allowing videos of our kid to be uploaded to Youtube/Facebook, etc., luckily there are consent forms now, but you have to be constantly vigilant, because sometimes the consent forms are ignored or you get e-mails saying 'if you object, react by the end of the day'. If they play at friend's houses, they typically have access to the same games as well. Do you also want to say 'no' to playing at other kids' homes?

It has been shown scientifically that social media, certain games, etc. are bad and nearly as addictive as heroin. Maybe it's time to make a law to forbid use by kids, just like we have laws that you cannot sell alcohol, drugs, or cigarettes to kids?

And again, we should find a privacy-preserving way to do it.

Well how do you tell your kid "no" when he asks for candy, when he can get as much as he wants at friend's houses, school, the library, or basically anywhere outside your house?

Edit: better exaple would be cigarettes, since that's something we as a society recognize is bad for kids and generally require proof of age if there is any doubt. Imagine if all your kid's friends smoked, and there were cigarette vending machines at school, and all you could do was say "no."