When I first tried to buy them on Sunday, the register wasn't ringing a discount at all. After 15 minutes on the phone with the help desk, she just rang me up at the regular price and gave me $10 cash. Went back yesterday and the register rang $10 off each card, but the cashier noticed that didn't match what their ad said, so she called help desk again and put in a "fix it ticket." Rang me up at regular price and gave me $10 cash. (As you can imagine, there are A LOT of cards at this location!) The same cashier from Sunday came by after about 5 minutes and recognized me as "the gift card lady", so I can't go back there again this week.
Went to a different OM instead, register rang $10 off each card, and cashier didn't bat an eye, but I could only buy one set. I'll be interested in seeing if the overly observant cashier and her "fix it ticket" has any impact on this promo for other stores.