There are a lot of things I'd like to see banned in public places because they irritate me. They include cell phone conversations - I have no interest in hearing what you and your friend are doing tonight or knowing about it. But I guess this would impinge on freedom of speech so I guess I'll accept it.
Smoking is another thing I'd like to see banned because it smells awful but I guess I can just get up and move somewhere else. At the end of the day smokers need to have a conscious, and be considerate to others about where they smoke, and the impact it has on others rather than be told where and when they can smoke. Unfortunately, the smoking habit is strong and usually overcomes consideration for others when the desire to smoke happens.