To illustrate, an instructive model is that of twenty men held up for robbery or ransom by a single man who has a gun and six bullets. They can overwhelm him if they are willing to lose six of themselves, if they have a means of deciding which six to lose. They can defeat him without loss if they can visibly commit themselves to a threat to do so, if they can simultaneously commit themselves to a promise to abstain from capital punishment, once they have caught him. He can deter their threat if he can visibly commit himself to shoot in disregard of any subsequent threat they might make, or if he can show that he could not believe their promise. … If the twenty cannot find a way to divide the risk, there may be no one to go first to carry out the threat, hence no way to make the threat persuasive; and if he can announce a formula for shooting, such as that those who move first get shot first, he can deter them unless they find a way to move together without a “first.” If fourteen of the twenty can overpower the remaining six and force them to advance, they can demonstrate that they could overwhelm the man; if so, the threat succeeds and the gunman surrenders, and even the six “expendables” gain through their own inability to avoid jeopardy. If the twenty could overwhelm the man but have no way of letting him escape, a promise of immunity may be necessary; but if they cannot deny their capacity to identify him and testify against him later, it may be necessary to let him take a hostage.

XREF: This echoes Schelling's coordination problems and free-rider logic familiar from game theory and collective action theory.

Thomas C. Schelling, The Strategy of Conflict, loc. 287