Yes, it is a real problem. The smoke bothers every non-smoker. But a complete ban is not necessary. I mean, those public places can save up some money so they can build special areas for non-smokers and those areas would be vent. This way would thank both parts: the part of population that smokes and love smoking while at a restaurant and the part of population that doesn't smoke and can't stand the smoke. So if somebody wants to smoke, let him do. As long as it doesn't socialy harm anyone. And by using this special areas for smokers, everyone would be happy and the restaurants would make profit.
P.S.: sorry for my bad english but it's not my native language. But i hope i proved my point.