The latter scenario is shockingly easy to build with modern cloud services. I once built a toy example that would track a given face through all the public camera streams in my city (Berlin) in a two day hackathon (and we all know how little coding gets done at those). And just like that, stalking is obsolete.

It's one of the only times in my life I've elected NOT to open source my work. As trivial as it was to build, I don't want to contribute anything at all to that creepy mess.

That was three years ago. My key takeaway: just assume scenario B is happening already.