It was the same night on our Western cruise last October and it was a difficult decision. Our DS5 decided to wear regular clothes to the Goofy Giggle Gala, but later told us "most" of the kids were in pajamas. Although when I picked him up, I only noticed a few in pajamas - so it may have just been that he noticed those more. We really didn't have enough time between picking him up at the club and the start of the pirate party on deck for him to change, so we just went with his pirate hat (the one with the striped bandana and mickey ears) for the party. (He chose not to wear his pirate costume to the Giggle Gala because he thought it might be "weird" - he had seen the DVD over and over and the kids on that are in pajamas.)
I totally agree that having these the same night is difficult! Since we prefer late seating, DS had to choose between the pirate theme in the dining room and Goofy (he chose Goofy, but is considering skipping Goofy this fall for the dining room). For many 5-7 year olds both the Goofy Giggle Gala and Pirate Night are highlights of the trip - it seems a shame to put them on the same night and force them to choose between them.
pdarrah
