My 2 cents…
Amazon can scan my files and find that I have uploaded movie and music rips. It is not illegal for me to possess rips of material that I have purchased. In many cases I have downloaded rips of content that I own. Many of you with slower machines likely do the same. With the advent of H.265 even people with extremely fast machines may well follow suit. There is no way for Amazon to tell whether or not the rips contravene copyright laws.
Amazon clearly states that you alone are responsible for ensuring your files are not contraband…
“You are solely responsible for Your Files and for complying with all applicable copyright and other laws, including import and export control laws and regulations, and with the terms of any licenses or agreements to which you are bound.”
So the problem, as I see it, is if you are found to be running a file sharing service. In that instance it doesn’t matter how you came to possess the content, you are breaking copyright laws by distributing it to others. This is, to the best of my knowledge, the action for which people have been viciously prosecuted in the USA. Simple possession would be extremely difficult to detect, prove, and prosecute.
Plex facilitates the viewing by others of content you choose to share with them. It does not allow them to easily make a copy or add it to their own library. This may or may not contravene copyright laws depending on where you live, with whom you share the content, how many others you share the content with, their relationship to you, etc… I have loaned CD’s, DVD’s, Bluray’s to friends in the past. Am I violating my countries copyright laws by doing so? Nope. Did they copy them? Maybe. Heck, my local library even lends them out.
Plex makes it easier to borrow content from a friend but much harder for them to keep a copy. Since it is, by design, private, requiring a personal invitation to connect. It is not only hard to detect but, in most countries, illegal to eavesdrop on. So, as the Plex moderators have already made clear… don’t run a file sharing service and you should be fine. Should. The risks, if any, are yours to assess give the specifics of your situation. The consequences, if any, are yours alone to bear.
(The foregoing should not be construed as legal advice. The author accepts no responsibility for any blah blah blah, lorem opium…)