I'm for Vigilanties, but what I'm even more for is Vigilante Force.
Take a number of people who have no distinctive way of dressing or anything like that. Give those people pistols and badges. And now give them the right to act with no consequences whenever somebody's health or safety is endangered. A guy talks shit and is acting violently on a train. A group of thugs bully somebody on the street. A drunk damages property.
The guy wouldn't actually have to shoot one bullet. But the fact that they, the Judges, can be everywhere, because of how incognito they are, and the fact that they CAN use their guns if the situation becomes difficult would, in my opinion, improve the overall safety of regular people like you and I.
Of course such an organisation would need very hard entry tests - mostly psychological. And of course there is place for screw-ups. But personally, I don't care much about people, and a few minor mistakes are justifiable if the hundreds of chavs, thugs and pure assholes fear threatened or bite the dust. If they strike fear into our hearts, it's high time they feel the same. And if you're a regular guy on the street, not doing anything wrong - you have nothing to worry about.
Such an organisation in a country like England would do wonders. You wouldn't believe how many useless, aggressive pricks you get in smaller cities here.