From Breitbart: The 3rd Circuit Court of Appeals threw out the FCC's $550,000 fine against CBS for Janet Jackson's "wardrobe malfunction" during the 2004 Superbowl. Applying classic administrative legal concepts, the Court held that the FCC acted arbitrarily. The Court ruled (correctly) that the FCC "cannot change a well-established course of action without supplying notice of and a reasoned explanation for its policy departure." Meaning, if you are going to do it to CBS - you have to do it to everyone.
Of course, I say it was no malfunction - Jackson intended it all along, although she may not have told CBS of her plans. One of the lines of the song she was performing with 90 million people watching was "[g]onna have you naked by the end of this song." Or maybe it was just a coincidence.