I wonder if there are cases of people leading batman style lives. Or even maybe Dexter style lives (going about dishing out illegal justice in their spare time).
One thing that comes to mind is from a movie I saw (maybe smoke signals?), where the native american tribe (living in modern times) had a traditional role of some people disguising and teaching other people a lesson.
As for the signalling problem, maybe something could be built with modern technologie (SMS, mobile internet, social networks).
In fact today I had this thought, fueled by paranoia: what if your child was abducted, but could send one last distress call. I suppose police wouldn't be able to block the roads in time to catch the abductor, but what if by a snowballing flash mob effect, all people would take to the street and blocked all roads until police would arrive? It would be a kind of distributed batman effect...