Here, Ars Technica complains about the MPAA buying some "private" TorrentSpy e-mails to use in its case against the organization. Now, I don't remember them complaining when any other set of "private" emails have been released to show some questionable activity by companies like Microsoft, Intel, or whomever.
 
In fact, I can remember them being all over such emails, with no compunctions whatever.