 McMahan argues that liability to be killed need not, in fact, presuppose responsibility for an unjustified threat. Instead, unjust combatants’ responsibility for just combatants’ reasonable beliefs that they are liable may be enough to ground forfeiture of their rights (McMahan 2011a). Some argue that combatants’ responsibility for being in the wrong place at the wrong time is enough (likening them to voluntary human  shields).[22]  More radically still, some philosophers abandon the insistence on individual responsibility, arguing that unjust combatants are collectively responsible for contributing to unjustified threats, even if they are individually ineffective (or even counterproductive) (Kamm 2004; Bazargan 2013).