IF, by chance, the store register is one of those that can identify cards through the BIN numbers and shows A GIFT FOR YOU or PREPAID CARD HOLDER as your name, it's useless to mask your GCs by putting your name on it or putting stickers to cover giftcard. IOW, the cashier doesn't have to see the card to know it's not a bank DC. It is best not to lie when asked if you're using a GC and if it's not allowed, just leave.