Соответствующая норма
Practice Relating to Rule 106. Conditions for Prisoner-of-War Status
Section A. Distinction from the civilian population
Spain’s LOAC Manual (2007) states:
Combatants must distinguish themselves from the civilian population:
(a) by carrying their arms openly at all times;
(b) by wearing a uniform or distinctive sign making them easily recognizable from a distance, although this obligation can be derogated from in exceptional circumstances. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 8.2.d.(2).