i think this thread should be considered in the context of vigilante justice, even though the 'crime' is mundane and the rational supported by a majority of the public.
kudra did the right thing, above, by being annoyed, asking, then bringing in outside authories when the person wasn't cooperative.
my ideals on public health are not really worth a broken nose, which is a very realistic outcome of smashing a strager's cigarette. i do care, however, about things affecting my health, so there is a responsiblity to either do something active to change the situation, or to remove myself from it.
in general, extremism begets extremism. in breaking the cigarette you're not even helping to change the smoker's behaviour --which was, more or less, the basic point.