You cannot compare a cruise to any main land dining event. We are on a ship and in the middle of the ocean. It is not like you can just get up and go anywhere else to eat. A person who wants to dine in the dining room on formal night should be allowed even if that person is not dresses up. This person paid the same fare as you did and is ENTITLED to eat where he or she so pleases, dressed to the hilt or not.