Back when I was still using P2P (last year) I received the same warning letter from Verizon. I usually shared only original works (music, vids, etc.) After downloading a dozen "fakes", I thought I'd be a good samaritan and label them as fakes, then share the files to let folks know not to waste their time.
So essentially, since the files were corrupt garbage, I was "turned in" for sharing a large file with the name of a copyrighted work.
