RIAA. Can they actually make this stick?

Say I Buy a Madonna CD and MP3 the tracks to my shared folder. It's My CD, my computer my shared folder. I'll do what I want with it. Then your shared folder or IP gets scanned or whatever (Sounds like BSH*T to me). How can you get a subpoena for nicking a file you bought???

Who knows that you actually downloaded this file or purchased it from a shop or payed download, it's not registered.

Sounds like it's a scam to stop people sharing files.

Your thoughts please..........