If all smokers retreated into a little room on their own and smoked themselves and other smokers to death I might very much regret that fact and might want to do as much as possible to prevent it, but it would not be an intrusion upon the health of the rest of us. The truth is that the exposure on a regular basis to other people's smoke can increase the risk of a variety of tobacco-related ailments by a factor of between 30% and 40%. Research is probably beginning to show that the figure is higher than that. It is hard to believe now that in theatres 30 or 40 years ago the entire audience would feel perfectly free to blow smoke in the direction of the unfortunate actors. It is so unthinkable nowadays. Having to breathe in smoke in cinemas was a regular feature until perhaps ten years ago. I used to have to inhale smoke in a restaurant until quite recently. When I still have to breathe in smoke in a pub it puts me at risk, first of all.