Hi. We are going on a 4 night in December and was reading that a lot of people do not dress up on the Wonder and for shorter cruises? This cruise is over NYE so I know there will be a party, but what about formal attire? Will we be out of place with tuxes and formal dresses? I would hate to pack all that for no reason. We took it all with us on a 7 night, but I haven't read much about 4 nights.