I have never heard of anyone actually being turned away from the dining room on formal night is they were not dressed "formally" on DCL but on Carnival they sure did...if you were in shorts they polietly asked you to change if you wanted to dine in the dining room.
I actually liked that they enforced the dress code on Carnival.
Formal wear means different things to different people. We don't dress in tuxes but hubby does wear a suit or a sport coat with button up shirt, tie and dockers and I wear a nice pantsuit, cocktail dress or sometimes even long gown.
As long as you look decent I don't think you will have a problem eating in the dining room.
I enjoy being in the atrium and seeing everyone dressed up...makes it a special evening IMO.
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