bought 13 Marriott gift cards across two orders. within 3 days of my purchase I checked each cards balance on the Marriott website. 7 of the gift cards had been used at least 10 months before my purchase and 2 of the gift cards were marked as fraudulent by Marriott. only 4 of the 13 gift cards were valid. that's a terrible success rate.
in addition, their claims form only accepts one gift card per claim so I had to submit 9 claims. and even though they were quick to resolve my claims (within one day) I have to wait 21 days before my credit is received (still waiting).
edit (25 Oct 2019): today is day-21 and my refund has not been received. i'll wait one more week before filing a fraud claim with my credit card.