Dave Nicklaus has an interesting discussion about a new study claiming that Illinois's smoking ban didn't hurt Illinois casinos. I am dubious of the study because, like most of the research on this question, it was funded by people with an interest in its outcome. In terms of its substance, the study seems to have addressed only a very narrow part of the claimed effect of the smoking ban: that people would go to casinos in neighboring states that allow smoking. More importantly, the discussion didn't mention the solid and independent research by Tom Garrett and Mike Pakko, which they summarize here. Garrett and Pakko found "that revenue and admissions at Illinois casinos declined by more than 20 percent ($400 million) and 12 percent, respectively. Calculations reveal that casino tax revenue to state and local governments declined by approximately $200 million."
Personally, I'm in favor of smoking bans, but I have no doubt that they hurt the business that they are imposed on. Research studies finding otherwise tend to be statistically inept (Pakko describes a hilarious case of this), so I discount them almost entirely. (Note that I'm too cheap to pay to read the new study discussed above, so I remain neutral on its statistical soundness.) Solid and honest arguments can be made that smoking bans are good ideas despite the cost they impose on some businesses. These should be the foci of the debate, not dubious claims that business owners don't know how their own businesses operate.