You can be casual all day. Most people walk around in their swim suits on the decks. They only recommend dressing for dinner, which means no shorts, jeans, etc...On the 4 night Wonder, a jacket for men was only recommended for 1 restaurant, unless you choose to do Palo, which is dressier as well. To me, that was part of the fun of being on a cruise as compared to anywhere else. The dining is an experience, not just eating. I think many people enjoy the atmosphere, although there are a few who'd rather stay in their shorts and t-shirts, but I think Disney continues this dress "code" for the majority who do enjoy it. It's really not that bad anyway. I wore capris, sundresses with sandals, that type of thing and my husband wore khakis and even jeans with a polo type shirt at the more casual restaurant.