I just looked on Navigators on Dave's site for the Wonder 4 day, and it does list a jacket as 'recommended' for Triton's. Although my husband enjoys bringing a tux for formal nights on cruises, he has already said that he is just bringing a dress pants and shirt for our Wonder trip since there is no 'formal night'. I hope he will not look out of place. But, I can't blame him for not wanting to bring a jacket for one night when we are spending 4 nights in WDW before 4 nights on the ship.