I actually was never bothered by second-hand smoke (I grew up with a lot of family who smoked indoors at reunions) until I quit after smoking for several years myself. I was always a "stopper" like most but eventually was forced to quit due to aggravation of chronic respiratory conditions and signs of developing acute ones. Ever since then, it can make me nauseous to the point of puking, and poorly ventilated places down in Vegas where I live now will have me seeing stars and stumbling. If I can smoke a cigar, the nausea will often subside, but the rest is likely a result of growing up around it and doing it in excess myself (I smoked 2 packs/day at peak when I was delivering pizzas before college). I also think in many ways it's my body's recognition that these toxins should not be welcome, a recognition that sadly is ignored when we hack uncontrollably on that first-ever drag.
I'm very libertarian to the point that conservatives and liberals alike will raise a brow to many of my assertions; but this is one of those arenas wherein common courtesy and decency has failed to regulate behavior, and in those arenas I have to concede to those who want the government to regulate otherwise personal decisions. Just as with banks, my concession is
extremely reluctant, and the people I hate most are the inconsiderate jerks who make heavy-handed regulation necessary with their own disregard for decency.

After all, consideration and decency are fundamental requirements for a liberty to be justifiably maintained.
All that being said, I still think it should be the business's choice. Fighting that goes into threatening much more valuable precedents, and keeping eminent domain at bay was a great one for a prior poster to point out in that category, even if it would've drifted off topic to explore in depth.