if the gift card is spent.. the gift card issuer will do a chargeback on tbhe merchant where the giftcard was spent?
Yes if the gift card is spent before the card owner claims chargeback than buyers may not loss anything. However if he have used those gift card to purchase some physical goods which need to be delivered to his address, he may get legal issue in future if the amount is quite big.
what about the merchant that the fraudster used to buy the products with the bad gift card?
does that merchant end up having to pay(via chargebacl) for doing the transaction with the customer who had the bad gift card?