I am very mixed on smoking bans. Before reading this group, I was totally opposed to them on the same grounds as Katana. In fact, if you will look over previous threads on the matter, you will see that I have typiferously opposed them.
However, my thinking has changed lately. Smoking bans are not needed for so that customers can sit in clean air. They are, however, justified on the grounds of worker health and safety.
Should an employee be forced to work in an unhealthy environment? Loggers do, but then, that risk is inherent in the profession. A logger who can't cut down a tree is not a logger. On the other hand, bar owners do not have to allow smoking to be bar owners. Therefore, the government can outlaw smoking to protect the workers.
We all get upset when there are deaths in coalmines, and everyone asks, should the government do more to require the employers to protect the health and safety of their employees? This is the same deal.
I agree with most of the comments here. Outlawing smoking on the grounds that it is annoying to customers unjustified. If you don't like smoke, don't go. It is my personal approach, and I will dispute anyone who thinks we should have a smoking ban because they, as customers, don't like smoke. Don't go.
However, the worker's rights issue is more difficult to argue against. Personally, my position has been swayed significantly because of it.