According to the complaint, GameStop acquires "additional personal information, including the cardholder's physical residential address, by pairing the PII (personal identification information) with the cardholder's name obtained from the credit card." Essentially, the suit alleges you're handing over a lot more than just a credit card number to GameStop when you swipe for your purchase.
"Such conduct is performed intentionally and without the knowledge or consent of the cardholder, and is of potentially great benefit to [GameStop]," the document adds. But how else would you be able to get Game Informer, right?
The class action suit will potentially apply to all Californian GameStop shoppers. IGN has posted a PDF copy of the suit in full.