The Hyatt!!! Many times I have seen women come in in dressy dresses with heels. The Hyatt, IMHO, is the most upscale casino and I've been in them all. I don't generally wear a t-shirt and shorts anywhere at night but have seen them in all casinos. Would say that the only place I've really seen dressed up was the Hyatt. Oh yeah, I forgot the night the bride came into Alhambra in her wedding dress
We went to Ruinas Del Mar at the Hyatt for an outstanding dinner and we got fairly dressed up, for us. I wore a dress and my husband wore khakis and a polo shirt. But the atmosphere there was more dressy than all of the other places we had gone to. After dinner, the bar at the Hyatt near the lobby was a beautiful place to just sit and listen to music. And walking around on the boardwalk at night you can get as fancy or casual as you want. It's great for people watching and so beautiful to just walk along the water.
A few years ago there was an older couple who showed up at Old Man and The Sea, man in a suit and the woman was wearing a fancy dress and boots (ok, the boots was really hilarious in the sand but that's another story). I am sure they would have appreciated being told to come more casual.
Years and years ago DH would bring one jacket to wear to Chez Mathilde as that was the only place that was more a "jacket" place. There is nowhere that people really "dress up" in Aruba. Even during NYE people will elevate somewhat but not what you would expect. Some do get really dressed but most not. I bring a dress for NYE but other than that evenings consist of a capris and DH brings one pair of pants but almost every evening he wears walking shorts. Shirt depends on the restaurant-golf shirt, nicer t-shirt or short sleeve "shirt".
Lisa's response was most appropriate. The original question was where could you go to be "dressed up". When we have friends that are coming to Aruba for the first time we always advise them not to expect to find anywhere that people "dress up". Other islands are different than Aruba as they do have places where a notched up dress code is appropriate. The original poster was asking "where" and Lisa told her that basically nowhere do people dress up. It was appropriate to tell her that she might be disappointed if that is what she wanted in an island for dinner places. Obviously, dinner clothes even casual can be a nicer version of what we would wear for touring, shopping, etc but that is an indvidual decision.