I mean technically that already happens in the UK - you can have sex legally at 16, but you can't take any pictures of you doing so until you are 18. So 2 consenting 17 year old teenagers cannot send indecent images of themselves to each other.

I seem to remember a case from a few years back, about a girl who got herself on the register for sending her boyfriend a picture of her naked or something.

Although it seems that the Protection of Children Act [1] I think (I'm not sure, it's hard to actually read with all the brackets ...) let's you do it if you are married (which you can also do at 16)

Any sane person would know that teenagers do what teenagers do ... having someone potentially going through those photos is such a strange and wrong approach

[1] https://www.legislation.gov.uk/ukpga/1978/37

It might also turn into a good teachable moment for teens about privacy, sharing, and technology. I don’t take a picture on a smartphone of anything that I wouldn’t want to make public, and I surely wouldn’t share or post it anywhere. If it leaves your device, it’s effectively public, regardless of whether whoever you sent it to tells you they’ll keep it “private”.

> If it leaves your device

Even this is naïve with Apple's new plan. How long do you really think they'll wait before a software update makes it apply to even things that don't leave your device?

This would be a much bigger step though, and any brand doing it, even Apple, would face very negative market effect.

It couldn't be legislated in the US because it would be unconstitutional to do so, almost impossible in the EU, possible in the UK/AU, even Canada (with the help of some creative rights busting from the Supreme Court, as they recently demonstrated).