I have a similar approach toward people that are smoking in non-smoking areas. If it appears that they are unaware that the area is a non-smoking area then I usually inform them very politely that they are in a non-smoking area and ask them to put out their cigarettes. If, on the other hand, it is obvious that they are defiantly smoking fully aware that it is a non-smoking area, just daring anyone to confront them for their violation (some of the more militant smokers appear to take great pleasure in this), then I'm a little less pleasant -- though even then I choose not to be abrasive, rude, or obnoxious. If they then choose to insist on smoking in a non-smoking area, then I have no problem with having them removed from the area by security (or if there is a local ordinance in effect having the police cite them).
Could you give us some examples of where this has taken place - the give and take, so to speak?
You know, what you said and what they said?