My recollection is any theme nights were in keeping with the suggested dress for that night and most passengers don't go crazy trying to dress the part. At most having a tropical Hawaii shirt or two is all you need. It was along the lines of a Caribbean Island night and a Mexican night, with appropriate buffets set up by the pools. It isn't an every night thing. It is more about pushing bar sales with specials on Corona beer and margaritas for the Mexican night, and rum concoctions on the Caribbean night.