This makes me think of people that add a “copyright” notice at the end of every comment

Ugh the ones with the “anti-AI” “licensing”? I honestly don’t know how they expect that to accomplish anything, other than look like a pretentious idiot.

Any better idea how to prevent scraping or, at least, be able to fight it after the fact?

For the US: you already have a copyright on everything you write. Adding CC-BY-NC grants others the right to republish it for non-commercial use, it does not remove any rights at all.

Yes, that is how that works, correct. CC-BY-NC specifically prevents commercial use and as far as I see that, that’s the point of those people that add that footer to their posts.

No, that’s not how it works. Commercial use is already prohibited by default. They are adding no new prohibitions. They are allowing use that is not allowed by default.

Not everywhere is the US. It’s not that simple here.