Why?
Drag your formal duds along if you wish.
Leave them at home if you wish.
The fashion police will be outside their jurisdiction while you are on board.
You will absolutely fit in whatever you decide to do.
Time for me to insert again: DRESS CODE = DRESS SUGGESTION.
Like it, don’t like it. It’s all the same to me. However, you cannot ignore the fact that it is what it is.
Please pass on giving your laundry to your RS on embarkation/turnaround day.
S/he is hammered with priority tasks that must be completed in a timely manner.