Related Rule
Greece
Practice Relating to Rule 35. Hospital and Safety Zones and Neutralized Zones
The Hellenic Navy’s International Law Manual (1995) provides:
In order to safeguard the unimpeded transfer of protected persons to hospital ships, a practice was established during the Falklands war, according to which a certain neutral area was demarcated named “Red Cross Boxes”. This practice, given the increased sensitivity of states regarding the protection of the right to life for non-combatants and persons hors de combat, tends to rapidly crystallize a customary rule, closely dependent upon the particular conditions under which naval warfare is waged and the vicinity where military operations are conducted. 
Greece, International Law Manual, Hellenic Navy General Staff, Directorate A2, Division IV, 1995, Chapter 7, Part I, § 7.