I don't think you can be certain offline, but it looks like the back of the card has an address where the money is stored. Presumably this will indicate if the

I don't think you can be certain offline, but it looks like the back of the card has an address where the money is stored. Presumably this will indicate if the card has been redeemed. It also lets you be sure someone didn't just print up some cards and hologram stickers themselves.