Ripped from a source you have legal access is undetectable in most cases.
Downloading a copy over the net that someone else ripped can be detectable.
That being said, I agree that piracy is just piracy. In my mind grabbing something from bittorrent/usenet is the same as using a VPN provider to stream from a different country, is the same as watching an illegal streamed copy on some website, is the same as ripping a copy from a friend/public library.
Did you pay to access it? Does the copyright holder make it freely available? No?
