Always remember that, except for V&A, these are NOT enforced codes. They are merely a suggested/recommended manner of dress. Actually, you will see many folks in shorts, etc at all WDW restaurants.
It really would be difficult to have it any other way, as people dining out are often going to (or coming from) theme parks etc. To make all of them dress up for dinner would -in many cases-be to lose their business. I can't see Disney doing that.