Nope, the Prinsendam is registered in the Netherlands.
I was on an Alaskan itinerary at the time. The casino Manager informed me that any winnings over $1300 required a W-2G issued by Carnival Cruise Casino. Interesting point though...was it only because we were in Alaskan waters? Or perhaps it is a policy of Carnival (HAL parent company & casino operator).
Anyone else experience this good fortune?