I bought two for the Delta Amex Suit case specials.
Then I bought 3 more for the Marriott 10% discount.
Then another one, which was ground shipped to a hotel after I checked out and it took a month for them to rescue it. I finally got a credit for the last one months later.

Too this day a year later, when I am going to use up the last of them at Marriott Hotels only, I am struggling with confirming there is still one of them not eluding my use of it.

The Marritt Guest Services is very relunctant to give meaningful information, other then give you the automated balance on the card. My conclusion is there is a high turnover of assistents answering the phone.