You must go way back -- to the '50s, when men wore suits, even tuxedoes, and women donned gowns and furs to go out to a casino at night. By the '60s, the era of fancy clothes was already history.
Or maybe you're referring to casinos abroad, especially in Europe, which people still get dressed up to visit.
Either way, apparently George Clooney, for one, agrees with you. He's proposing a return to the bygone formal-dress era for a new $3 billion condo-hotel-casino, Las Ramblas*, which he's an investor in and front man for. Clooney and his partners are planning a huge residential, retail, and entertainment complex, with 4,400 hotel-, condo-, and condo-hotel units, a 500,000-square-foot mall, and a smallish upscale casino -- which could have a dress code.
Good luck to him. The consensus around town, as expressed in a story by Liz Benston in the Las Vegas Sun (9/30/5), is that it doesn't make much sense. Younger people, for one group, won't don jackets and evening wear to go to a casino, no matter how much money they have. Likewise, many affluent people, no matter their age, like to blend in with the crowd. And the vast mass market, to which Las Vegas has catered since the '50s, prefers to dress down when it plays slots, goes to buffets, and sees shows.
In addition, it's possible that a casino dress code would be disallowed by Nevada gambling regulators, who'd look askance at a casino that barred entry to people not wearing "proper" attire.
Ultimately, it's clear that Clooney and crew want to create an upscale elegant environment. They can strongly encourage business attire and they can subtlly discourage dressed-down patrons. But it's questionable whether they could impose a strict dress code. And it's highly doubtful that any other casino in its right mind would even try.
*Since this answer was originally penned, word is that, like so many other ambitious announcements of recent months, the Las Ramblas project -- and its proposed dress code -- is to be abandoned.
