> unless there is some reasonable person standard applied here like 'everyone knows Harry Potter, and thus they should know it is obviously not CC0'

Yes there's an expectation that you put in some minimum amount of effort. The license issue here is not subtle, the Kaggle page says they just downloaded the eBooks and converted them to txt. The author is clearly familiar enough with HP to know that it's not old enough to be public domain, and the Kaggle page makes it pretty clear that they didn't get some kind of special permission.

If you want to get more specific on the legal side then copyright infringement does not require that you _knew_ you were infringing on the copyright, it's still infringement either way and you can be made to pay damages. It's entirely on you to verify the license.

> unless there is some reasonable person standard applied here like 'everyone knows Harry Potter, and thus they should know it is obviously not CC0'

Why wouldn't that apply?

Copyright infringement is a strict liability tort in the US. Willful infringement can result in harsher penalties, but being mistaken about the copyright status is not a valid defense.

The article author and the uploader should _BOTH_ be sentient enough to engage brain and not just ignore it because they feel "it's an abstract concept I'd not get in trouble for when not working in the US or EU".