Your dress code issue was pretty ridiculous, IMO. On almost every cruise it is expected to dress up for dinner. That is one of my favorite parts about cruising. We have used Celebrity Cruises a couple of times and they require formal attire on 3 nights. I love this and wish the days of the tux were still around. Nothing like putting on my tuxedo and escorting my wife to the dining room for a nice, romantic dinner. And Disney would be the perfect atmosphere for this type of formality, similar to V & A at WDW.
If I saw someone sitting next to us in jeans and tee-shirt, I'd probably throw their empty Coors Lite can at them.