Successfully used at Marriott Waikoloa on Big Island of Hawaii.

Had many separate stays due to limited night availability during a conference and using 35k and 50k nights from multiple accounts. I basically went to front desk once a day to settle my bill via giftcard. By the end a bunch of their staff brushed up on the use of givex

Marriott Victoria BC also processed the giftcard no problem, at close to spot rate last year.

Delta Kamloops BC processed giftcard on day of checkout, was CAD GC and a CAD bill so no forex involved