score:10
The relevant regulation (mainly the first) in WW1 would appear to be:
Article 9 of the 1906 Geneva Convention provides:
The personnel charged exclusively with the removal, transportation, and treatment of the sick and wounded, as well as with the administration of sanitary formations and establishments … shall be respected and protected under all circumstances. If they fall into the hands of the enemy they shall not be considered as prisoners of war.
Article 10 of the 1906 Geneva Convention provides:
The personnel of volunteer aid societies, duly recognized and authorized by their own governments, who are employed in the sanitary formations and establishments of armies, are assimilated to the personnel contemplated in the preceding article, upon condition that the said personnel shall be subject to military laws and regulations. Each state shall make known to the other, either in time of peace or at the opening, or during the progress of hostilities, and in any case before actual employment, the names of the societies which it has authorized to render assistance, under its responsibility, in the official sanitary service of its armies.
Now the question is: "Is someone wearing medical insignia, such as a red-cross arm band, which is tantamount to claiming protection under these regulations, while taking part in combat in breach of these regulations?" If the answer is yes, then they are in breach of the laws of war and so a war criminal.
Upvote:1
In 1946, a German soldier, Heinz Hagendorf, was found guilty by a U.S. military tribunal at the Dachau Trials and sentenced to six months imprisonment for having "wrongfully used the Red Cross emblem in a combat zone by firing a weapon at American soldiers from an enemy ambulance displaying such emblem."
Simulation of protected status by using the distinctive emblems of the Geneva Conventions:
It is a serious breach of the laws of war when soldiers use these signs [red cross, red crescent and red shield of David] to protect or hide military activities.
These appear to confirm that the actions of the nurse in question were a violation of the rules of war.
Her mitigating circumstance is the lack of premeditation (i.e., she went to battle without prior intent to lead the final assault).