1) American military slang for adolescent hit-and-run thieves in occupied countries who grab anything not well-secured or well-guarded. The most common item stolen are soldier's sunglasses (like Ray-Bans and Gargoyles, thus the term.
By extension, the term is also used for adolescent refugees and beggars.
"The locals have a trick where they leave a string of Ray-Ban Bandits by the convoy routes to beg for food or steal anything that falls off the trucks. Then they beat the poor starving bastards and take the stuff away from them so they can sell it on the black market..."