The reason why they state that the first night is casual is because there may be many people that will not have received their luggage by dinnertime. Carnival has taken this into consideration and does allow you in the dining room the first night in whatever you arrived in. Fortunately, we had late seating and our luggage arrived at our stateroom in time for us to shower and change.
Sovereign of The Seas - 9/98
Imagination - 10/2000
Glory - 10/03