It was not when we were there. Men came into Feathers in Hawaiian shirts, slip flops and cargo shorts. Women can wear dressier flip flops and open toed shoes of course. Not the rubbery or beachy ones. Men are supposed to have closed toe shoes or dressy closed toe sandals. It's just frustrating sometimes when you dress up and are sort of uncomfortable but others just stroll in wearing whatever.
We've been to CSA four times, most recently in January of this year. During each trip, we have seen gentlemen asked to leave Feathers because they were wearing either: shorts; flip-flops; or a t-shirt. Other than that, both men and women can wear flip-flops to the other restaurants.
I really don't understand why anyone cares what anyone else wears.
It's all a matter of preference, of course. My wife and I will be making our first trip to a first-class resort when we arrive at CTI in January. We are looking forward to all of the casual outdoor activities during the day and having a slightly more formal dinner setting to cap each day and make the end of each day special. Not all dinner venues need to be upscale however we would be disappointed if at least one wasn't. We don't want to dress the part only to have everyone around us look like they just came in from mowing the lawn! Not for dinner, anyway.