> So we're locking a per-user DNS choice in?

Sure, or per-device, or per-network, or per-organization. It depends on how each particular person wants to implement it.

> As you say, I can see a few ways around this ;)

Yes, notably less than the current proposal. Which, again, will just straight-up not work.

> f something screws up and Little Timmy gets to see some boobies, who gets blamed?

I think this really hit the nail on the head. None of this is about solving problems or helping little Timmy. It's about accountability management.

If we implement the OS syscall, then Meta gets to point their grimey finger at someone else while they continue to fuel genocide in Myanmar.

> Did the parents actually configure this themselves? If so, who taught them how to do that? Or did they buy the machine pre-configured? So does the vendor take responsibility?

Well, um, both. You can configure your router, sure, or your Linux computer. But I imagine a new iPhone would just come with a checkbox you can check at account creation time. Again, very similar to this proposal, except it works.