Соответствующая норма
Practice Relating to Rule 128. Release and Return of Persons Deprived of Their Liberty
Section D. Voluntary nature of return
Mexico’s Army and Air Force Manual (2009) states:
193. The [1949 Geneva] Convention [III] provides for direct repatriation (return to country of origin) and hospitalization in a neutral country:
C. no sick or injured prisoner of war may be repatriated against his will during hostilities. 
Mexico, Manual de Derecho Internacional Humanitario para el Ejército y la Fuerza Área Mexicanos, Ministry of National Defence, June 2009, § 193(C).