I think it would depend on what type of disney gift cards they are. If they are disneystore, catalog, online gift cards, I would say no, probably not. I would also guess that the Disneyland gift cards could not be used aboard either, (especially since they do state they may only be used at Disneyland (which I think the store ones state only good for store)). If they are through the cruise (I remember reading there is someway to do something like this) then I would say yes. If WDW has gift cards, I would see what it says.
Disney Gift cards are not honored on board the ships. It is my understanding they can only be used at the Disney Stores and cannot be used for park admission tickets nor Disney Dollars.
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