This is why the law tends to fall back on what a hypothetical "reasonable person" would think.
I'm not as much of a hardliner as rayiner on this particular case as I think there are some facts in favor of thinking of these documents as public:
- it was a government website
- it was specifically set up for the purpose of sharing foia requests
- the data in the documents was not easily identifiable as private
But when it comes to the general principle where some HNers seem to think "If the webserver responds with a 200 then it's perfectly fine." I have to disagree.
Imagine a different scenario in which we were talking about tax returns instead of foia requests. You're looking at yours at http://www.canadataxes.com/return?id=1234 and you realize that if you inc the ID you get the tax return of some other random Canadian citizen. In that case it would be immediately obvious that someone had made a mistake and you were accessing information you shouldn't. A "reasonable person" would understand that a mistake had been made. It would then be clearly illegal to write a script to scrape down the docs for every ID.
in the context of the article and the problem at hand, the teenager downloaded a bunch of things that were supposed to be public access, but also accidentally downloaded some things that were confidential though not clearly marked as such (im assuming based on available information) and so the only real way he would have known they were confidential was if he actually perused the contents of them. that would be like having a room that is private property and off-limits, and it is marked as such, but the marking is inside the room and can only be seen by entering it and as such violating the private nature of said room. but really these are all just my thoughts on it and i certainly don't think i'm right or anything. it's just fun to talk ya know