Well, based on our cruise on the Carnival Glory in December, people are now allowed to be wearing shorts there as well, even on formal night!
Had a guy walk into the dining room in front of me wearing a t-shirt, shorts, and flip flops!! And this was on formal night. When I asked the matre'd if such attire was allowed, her comment was, "We no longer stop them or confront them."
The next night, I watched 3 guys walk into the dining room wearing muscle t-shirts (no arms). Rather disgusting, actually. And then in the specialty restaurant, Emerald Steakhouse, we were told proper attire was 'cruise elegant', yet the guy sitting behind us was wearing a t-shirt, jeans, tennis shoes, and a baseball hat that he kept on throughout the entire dinner!
Yes, this was Carnival and other cruise lines are better, but I imagine it won't be too long before formal night and nice attire for dinner is a thing of the past.