We always tell parents of small children (and even younger teens) about the warning labels and what they mean (as well as ratings on games and movies). The Wal-Mart employees had NO way of knowing that this content would be on the CD.
However, I do think that BOTH the father in question AND Wal-Mart could have a case against the RECORD COMPANY. I'm hoping that the civil case against Wal-Mart is dropped and that they both persue this avenue.