On our recent Solstice sailing (7/1) we had folks yelling off the balconies, smoking pot in their staterooms, endlessly slamming doors, coughing & sneezing as they pleased**, leaving overflowing trays of room service trays for others to step over, doing laps in a crowded Solarium pool, crowding the hot tubs with 5, 6, 7 people (where is says capacity of 3), soooooooooo... we were happy that folks were clothed to come into the dining room!
That being said...on the first night of the cruise there tends to be a more casual dress code because folks have been travelling and may not have their luggage yet etc... On the last night the dress may be more casual because folks have packed up.
**About the coughing & sneezing...there was a lot of this along with the loud claim of "It's Allergies"! It was disgusting! **