For the 2013 Sports Illustrated Swimsuit Issue, the magazine photographed models on all 7 continents. A world tour of ill-fitting "swim" wear! But sometimes a half-naked lady standing in front of a gorgeous natural backdrop just isn't enough. So the photographers used natives as props.
Using people of color as background or extras is a popular fashion trope, whether it's Nylon magazine, the Free People catalog, British Vogue or J. Crew. But although it's prevalent, it's very distasteful.