The suit doesn't claim that actual identity theft has occurred as a result of that information being printed, only that it “could” happen. The Federal Credit Reporting Act, which went into place four years ago largely due to concerns of fraud, frowns upon putting the expiration date on paper receipts:
This violates a 2003 amendment to the FCRA which states: "No person that accepts credit cards or debit cards for the transaction of business shall print more than the last five digits of the card number or the expiration date upon any receipt provided to the card holder at the point of sale or transaction."
In that instance, the case does make a valid point, on top of another point regarding a three-year grace period to change this practice. As usual, Apple will not comment on the case, which is a growing number against Apple for violations of the FCRA.
I don't really see any way out of this for Apple other than changing their practices, since there truly is no excuse for putting that sort of information on a receipt.