Inspired by some things I've been reading: if you have a creative work which copyright law forbids you from distributing, and you're careless enough to leave a copy of the work in a situation where someone else can easily make a copy of it, would that count as distribution for purposes of a copyright infringement lawsuit? Or do you have to have the intent to distribute it for the lawsuit to be likely to succeed?
The (hypothetical) situation I had in mind for this is that a group of friends pool their resources and acquire a shared file server. They all trust each other and know not to use the server for sensitive data, so they don't bother to set up access controls that would prevent them from viewing each others' files. Now, suppose one of them uploads a copy of some copyrighted material to the server. It's something which they have the legal right to possess, but not to distribute, and (I forgot to mention this originally) their reason for uploading it is purely personal. For example, the material might be a rip of a DVD that they own which they want to transfer to their phone, or a legally acquired piece of software that they want to back up. The other friends are not told about the upload, but - critically - the uploader doesn't take measures to prevent them from accessing it either (like making it non-world-readable). So the file is sitting there unprotected, and any of the other users could make a copy of the material if they happen to find it. If they do, is the original uploader then liable for distribution, same as if they had shared the work intentionally?
I scanned through what seemed to be the relevant parts of copyright law, e.g. 17 U.S.C 106, 501, and 506, and 512 but didn't find any clear statement on the topic. Section 506 says that willful infringement is required for a judgment of criminal copyright infringement, but what about a non-criminal judgment?
If there has been an actual court case testing similar circumstances, I would love to have a reference to it, but I'm also interested in links to speculation from legal experts or other relevant resources.