Most hotels don't have a clue what these cards are. Essentially they are processed as a Visa card without the first digit (4). At least there is a lengthy delay in checkout for processing giftcards. Why doesn't Marriott just put them out as Visa cards? That would avoid so much confusion. I was unable to process my nearly 500$ balance on my Gift card at two recent stays and just gave up trying to use up that balance. It's really frustrating indeed, and will make me think twice about purchasing them again.