Why was it an issue?

The Geneva Conventions of 1864, 1906 and 1929.

The first three Geneva Conventions were mainly concerned with the treatment of prisoners of war, wounded and sick soldiers and  members of armed forces shipwrecked  at sea.  This reflected the nature of war at that time. Nevertheless the 1864 Geneva Convention also recognised that civilians required protection during times of war, particularly those who might be sheltering wounded combatants. 


Article 5 of the 1864 Convention stated  that inhabitants sheltering wounded combatants should be protected and treated with respect:   


Inhabitants of the country who bring help to the wounded shall be respected and shall remain free. Generals of the belligerent Powers shall make it their duty to notify the inhabitants of the appeal made to their humanity, and of the neutrality which humane conduct will confer. The presence of any wounded combatant receiving shelter and care in a house shall ensure its protection.