Matthew is right. The meal plan money is different from the "Cardinal Cash" money, even though it is on the same card. Meal plan money is the mandatory fee that is charged to students and can only be used at the on-campus dining facilities (Sodexo). Cardinal Cash works like a standard debit card - students have to add money to their account before they can use it. Unfortunately, the university has not done a very good job of explaining the difference to students so a lot of them get upset and can't understand why their card is declined at one of the restaurants when they are sure they have meal plan money on it.
Some of the restaurants in the old Masterson's location accept Cardinal Cash, but none are part of the meal plan. Of course the university charges exorbitant fees to businesses who accept Cardinal Cash so there is not much incentive to accept it, other than as a marketing ploy.