The German raiders' strikes against shipping in the South Pacific fuelled fears that enemy spies were operating in local ports. Posters, like this, one warned the New Zealand public that 'loose lips might sink ships'.
'They Shall Not Perish' poster by Douglas Volk, 1918 - used by the American Committee for Relief in the Near East to raise money to assist Armenian refugees forcibly displaced by the Ottoman Empire during the First World War.