Every US visitors are deignated a potential draft ranking. When US goes into a war and when existing military force isn't enough, they draft the citizens. If that's not enough they draft the visitors. Visitors are thus potentially ranked for their position. No star means you are just a corporal. One star means you are a brigadier, 2 means geneal and 3 means major general. These designations are random and only activated when the country goes into a big war.