[Jeffery]

However claiming as uniforms any clothing is disingenious. And wearing the uniform of the enemy? I seem to remember a bunch of Nazis being shoot out of hand for playing that game. Definitely still non-uniformed illegal combatants.

Oh and this is interesting... The rule is you can use the uniforms of the enemy, but not during Combat. e.g. if you don uniforms which make you look like the enemy, sneak around their line, then put on something distinguishing, lets say a large piece of red cloth tied to your arm, you can then legitimately open fire. If you do not make some effort to distinguish yourselves, its a war crime.

Theoretically you could wear any clothing you wanted so long as there is some common identifying mark. If one group all wore a certain type of turban, or a certain shirt, and of course as I mentioned earlier tying a cloth to your arm has been a common historical technique.

50. Treachery or Perfidy
Ruses of war are legitimate so long as they do not involve treachery or perfidy on the part of the belligerent resorting to them. They are, however, forbidden if they contravene any generally accepted rule.

The line of demarcation between legitimate ruses and forbidden acts of perfidy is sometimes indistinct, but the following examples indicate the correct principles. It would be an improper practice to secure an advantage of the enemy by deliberate lying or misleading conduct which involves a breach of faith, or when there is a moral obligation to speak the truth. For example, it is improper to feign surrender so as to secure an advantage over the opposing belligerent thereby. So similarly, to broadcast to the enemy that an armistice had been agreed upon when such is not the case would be treacherous. On the other hand, it is a perfectly proper ruse to summon a force to surrender on the ground that it is surrounded and thereby induce such surrender with a small force.

Treacherous or perfidious conduct in war is forbidden because it destroys the basis for a restoration of peace short of the complete annihilation of one belligerent by the other.

51. Legitimate Ruses
Among legitimate ruses may be counted surprises, ambushes, feigning attacks, retreats, or flights, simulating quiet and inactivity, use of small forces to simulate large units, transmitting false or misleading radio or telephone messages, deception of the enemy by bogus orders purporting to have been issued by the enemy commander, making use of the enemy's signals and passwords, pretending to communicate with troops or reinforcements which have no existence, deceptive supply movements, deliberate planting of false information use of spies and secret agents, moving landmarks, putting up dummy guns and vehicles or laying dummy mines, erection of dummy installations and airfields, removing unit identifications from uniforms, use of signal deceptive measures, and psychological warfare activities.

52. Improper Use of Identifying Devices
It is especially forbidden * * * to make improper use of a flag of truce, of the national flag, or of the military insignia and uniform of the enemy, as well as the distinctive badges of the Geneva Convention. (HR, art. 23, par. (f).)

53. Flags of Truce
Flags of truce must not be used surreptitiously to obtain military information or merely to obtain time to effect a retreat or secure reinforcements or to feign a surrender in order to surprise an enemy. An officer receiving them is not on this account absolved from the duty of exercising proper precautions with regard to them.

54. National Flags, Insignia, and Uniforms as a Ruse
In practice, it has been authorized to make use of national flags, insignia, and uniforms as a ruse. The foregoing rule (HR, art. 23, par. (f)) does not prohibit such employment, but does prohibit their improper use. It is certainly forbidden to employ them during combat, but their use at other times is not forbidden. Law of Land Warfare, Field Manual 27-10 Chapter 2

FM 27-10 Chptr 2 Hostilities

So in this case, likely illegal