Not only no shorts or sneakers, if memory serves me correctly, you had to wear a sport jacket (at least in the evening) when my wife and I tried to visit the casino a few years ago. I think I remember that I could have rented a sport jacket, but the price just didn't make it worth it. I sent my wife up to get a souvenir chip while I waited in the lobby - any dress code for a woman is hard to enforce (not that my wife wasn't nicely dressed).