> that solution has already failed.

Yes, granted, a globally enforced whitelist probably wouldn't work. I'm referring to bespoke lists that parents control. I know plenty of parents that use this. e.g. here's Apple's feature:

https://support.apple.com/en-us/105121#:~:text=Prevent%20ina...

> It works for websites because they can cleanly identify a child and filter content if appropriate.

This still doesn't solve the problem of different jurisdictions and culture wars of what is or isn't appropriate for kids. All this does is move the liability upstream to websites instead of the devices. That is, instead of the browser deciding what's appropriate, now Youtube, Reddit, etc have to decide. And, as we've seen with the OSA in the UK, typically smaller platforms can't handle the enforcement cost so they just shut down entirely.

https://onlinesafetyact.co.uk/in_memoriam/

The larger platforms often use overbroad CYA measures and throw up age verification where they don't need to (Reddit has done this in the EU), or just ban minors (Anthropic and character.ai did this).

As far as blocking explicit content, a self-labeling requirement like RTA accomplishes the same thing as a "this is a child" header but without the liability CYA and without the privacy concerns.

Where the "this is a child" header solution could theoretically win is allowing kids to access websites in a limited child-safe way, e.g. going to Reddit in child mode automatically shuts off certain subreddits. But, as we've seen, it just doesn't work well in practice and usually frustrates parents by overly broad content policing and liability theater. Kids are also at different levels of maturity and I've seen them get frustrated when they're binned into age categories that they feel they don't deserve. e.g. a 12 year old might be plenty mature enough for the 13-16 age category.

But my real objection to the "this is a child header" is the privacy risk and surveillance risk. I don't think it's worth it.