THe RIAA and likely MPAA r looking for large quantity file shares to prosecute. They are doing this by seeking out their intellectual property on the lists of files users share. It is likely that u r curently sharing ur playlists with the entirety of ur music library which makes it easy for them to simply search fro .m3u files and log user names to the files they download and then proceed with legal action. SO STOP SHARING UR PLAYLIST!