Smoking ban and workers
What you write about customers voting with their feet on whether a bar should allow smoking makes sense. In this state, though, the pro-ban forces made the argument about the health of bar employees, whose choice about smoking is limited to choosing whether or not to work at a particular bar. (Usually customers have more voice than employees, of course.) What's your response to the concept that smoking bans should occur because of the bad effects of second-hand smoke on those bars' employees?
My answer is that the argument for workers is exactly the same as it is for customers. If employees are asked to work in less desirable place, you will have to pay them more to get them to do it. Firms compete for workers on the basis of salary and other dimensions, such as work place quality. Firms have to see how much they have to pay these workers to work in a smoke filled room and how much smoking customers are willing to pay for that service. If the cost of the workers is less than what the customers are willing to pay, some restaurants will offer smoking.