The card information is a very big deal. First of all, the only argument Nifong gave for it was to verify any statements the potential witnesses made. That flimsy argument was not enough to overcome the FERPA protections.
Second, Nifong wanted to go on a fishing expedition with that information. He is not entitled to it under FERPA. No player is obligated to talk to Nifong. I don't think that Nifong knows for certain who attended the party. And maybe he would if he had properly investigated this case rather than turned it into a plotical tool to win the primary.
Loved the line from the defense attorney who said that there wasn't a card swipe at 610 Buchanan! Nifong particularly wants to know where Collin was.
Third, the release of data card information on such a flimsy argument would be chilling. This is private information protected by federal law. There is no reason to release this information to Nifong. He's already shown that he has abused his position of power. Information is power. I'm glad someone reined him in.