But you are ignoring the view point of the waitstaff that chooses to smoke.
As to office workers, many places still permit smoking in private offices or designated smoking lounges in order to accomodate both.
When Delaware instituted it's smoking ban that right was taken away from not only the employees but the business owners as well.
I'm certain that the resturant has a break room, or can provide someplace for the waitstaff to go, when they want to smoke. Just like any other place of work.
From the perspective of the customer, I agree with your point of view. I don't want the gov't mandating smoke-free resturants; as the proprietor should make that decision. However, from the point of view of the employee's, the OSHA laws protect them; just like they protect us.