If only it was as simple as flicking a light-switch. The risk of violence aside, one guy getting unruly surrounded by 3 first time customers means 3 first customers that likely won't return because they don't like the athmosphere. One of the oldest strawmen used by the pro-smoker crowd, find a new one please. And there will always be violence in pubs, but a smoker not getting his way is one of the few that you can always count on, from what I've been told. But that's besides the issue, the real issue is the immediate and ever present health danger that is smoke. No, smokers are occasionally their best customers. Please don't think it's some kind of general rule. Six months after the beginning smoking ban, ask the owner of your favorite pub how much he misses you being able to smoke in there.