A couple years ago, Amazon had Johnny Cash's version of Casey Jones from the 1994 "Blood Sweat and Tears" album available for download. They have since taken it down, which isn't altogether surprising, these things come and go. But I discovered after a search that thousands of links to this song, on YouTube, on foreign sites, etc., have ALL been taken down.
Apparently a "Cease and Desist" letter went out to ANYBODY who had it listed in any way. Ironically, other songs from the same album have NOT been blacklisted. My guess is that, since Johnny's gone, the record company is getting ready to put together one of those $60 a set collections and wants to make certain that the songs they want on it are available nowhere else.
I didn't get the cease and desist letter, since I was actually just linking to the Amazon site, but I've seen a copy of it they sent to someone else.
In other words, if you have that recording in your collection, mp3, vinyl, cassette, 8-track, or CD, guard it with your life.