Perfidy and Treachery
The Crimes of War Project has a list of terms many of which relate, or are bound to relate to combat in places like the Sunni Triangle. One of the more interesting definitions is the notion of "Perfidy and Treachery" and its relationship to the ruse de guerre. What is interesting in this discussion is the distinction drawn between what seems barbarous, such as the massacre at Srebrenica, and the technical illegality of using neutral emblems in a perfidious manner.
... Bosnian Serb soldiers wearing stolen UN uniforms and driving stolen UN vehicles announced over megaphones that that they were UN peacekeepers and that they were prepared to oversee the Bosnian Muslims’ surrender and guarantee they would not be harmed. Disoriented and exhausted, many Bosnian Muslims fell for the lie. It was only after they had surrendered that they discovered their fatal mistake. For in surrendering, they were going to their deaths. Those whom the Serbs got their hands on were killed by firing squad.
Srebrenica was the worst massacre in Europe since World War II. The shock at what took place there was so great that to separate war crimes from entirely licit military actions seemed, and in many ways still seems, almost obscene. And yet from the point of view of international humanitarian law, the ambushes the Serbs sprang on the fleeing Bosnians were legal ruses soldiers can employ in wartime. Investigators for the International War Crimes Tribunal for the Former Yugoslavia said the fact that many of those in the retreating column were Bosnian government soldiers made the column a military threat and thus a legitimate target. In legal terms, the Bosnian Serb ambushes did not lull the Bosnian Muslims into a false sense of protection under international law, rather they led them to miscalculate the nature of the threat.
What was entirely criminal was the Bosnian Serbs’ use of UN emblems and matériel to lure the fleeing Muslims to surrender—a clear example of a war crime. The prohibition in modern times against what is alternatively called “perfidy” and “treachery” goes back to the American Civil War.
... Other examples of perfidy are feigning to negotiate under a flag of truce or surrender, feigning to be incapacitated by wounds or sickness, and feigning of civilian, noncombatant status. Article 39 prohibits the use of flags, military emblems, insignia, or uniforms of the opposing side at the time of an attack in order to protect or impede military operations.
... But the protocol states explicitly that ruses of war are not prohibited. A ruse is an act that is intended to mislead an adversary or to “induce him to act recklessly” but which infringe no rule of armed conflict and do not attempt to gain his confidence by assuring protection under law. Camouflage, decoys, mock operations, and misinformation are all permitted ruses. An example of a legal ruse was when U.S. forces gathered at sea during the Gulf War to trick Iraq into thinking an amphibious assault was imminent; the attack eventually came by land. Another example might be sending a bomber toward barracks in order to draw air defense away from a shipyard.