I just got off the Miracle. On FORMAL NIGHTS: A very few men wore tuxedos, about 1/2 wore a jacket, many were wearing a dress shirt with or without a tie. No need to stress it. Dress comfortably. You will be able to eat comfortably with no pressure if you dress 'nicely' on formal night.
On regular nights, clean fresh clothes, but "no shorts or bathrobes." That's exactly what the sign says. Many people wore jeans, polo shirts, very casual dress. be comfortable, be happy, relax, it is your vacation, people are there to enjoy and have fun. And because of these boards, I was looking very closely to see what the fuss about dress was all about. On the Miracle, there was no fuss. It seems to be a message board thing. Enjoy!!!!!!