The Westin Casuarina Las Vegas' website says,
As of January 12, 2006, we are a non-smoking hotel; all guest rooms are non-smoking. A cleaning fee will be charged to those who violate the non-smoking policy. Smoking is still permitted in the casino, lobby bar, and pool areas. Smoking is not permitted in the lobby, front desk, VIP or meeting areas, or in food and beverage outlets. Please contact the hotel for further information.
So much for fulfilling my hopes for a non-smoking casino. I guess the lobby bar is neither part of the lobby nor a food and beverage outlet. I understand that the casino is operated by a third party.