Related Rule
United States of America
Practice Relating to Rule 65. Perfidy
Section C. Simulation of being disabled by injuries or sickness
The US Air Force Pamphlet (1976) considers that:
Since situations of distress occur during times of armed conflict, as well as peace, and frequently suggest that the persons involved are hors de combat, feigning distress or death, wounds or sickness in order to resume hostilities constitutes perfidy in ground combat. However, a sick or wounded combatant does not commit perfidy by calling for and receiving medical aid even though he may intend immediately to resume fighting … In aerial warfare, it is forbidden to improperly use internationally recognized distress signals to lure the enemy into a false sense of security and then attack. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 8-6(a); see also § 8-3(a).
The US Naval Handbook (1995) states:
It is a violation of the law of armed conflict to kill, injure or capture the enemy … by feigning shipwreck, sickness, [or] wounds … A surprise attack by a person feigning shipwreck, sickness, or wounds undermines the protected status of those rendered incapable of combat … Such acts of perfidy are punishable war crimes. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 12.7.
The US Naval Handbook (2007) states:
It is a violation of the law of armed conflict to kill, injure, or capture the enemy … by feigning shipwreck, sickness, [or] wounds … A surprise attack by a person feigning shipwreck, sickness, or wounds undermines the protected status of those rendered incapable of combat. Such acts of perfidy are punishable war crimes. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 12.7.
The US Manual for Military Commissions (2010), Part IV, Crimes and Elements, states: “One may commit an act of treachery or perfidy by, for example … feigning incapacitation by wounds or sickness”. 
United States, Manual for Military Commissions, published in implementation of Chapter 47A of Title 10, United States Code, as amended by the Military Commissions Act of 2009, 10 U.S.C, §§ 948a, et seq., 27 April 2010, § 5(17)(c)(4), p. IV-15.