Which other vigilante groups would engage in reprisal though? A theory of deterrence (via punishment) requires a credible threat to retaliate and the means to d

Which other vigilante groups would engage in reprisal though? A theory of deterrence (via punishment) requires a credible threat to retaliate and the means to do so. When you don't even know whether there is another group(s) trying to deter you it's that much less clear whether you should refrain from that action or not. Even when you can identify a threat vigilante group, would they really start a war with your group over a single person? Just as in international politics, the answer is not obviously yes.