So the caller's making an interesting association between the military and the Greek letter lambda, but I think this caller is a little simplistic, about just like, ah, it's from the shield or whatever. If you look into it, you'll find a bunch of fraternities and sororities that are military in nature that use the letter lambda in their name, and even when it's not the first letter, like in the case of Kappa Lambda Chi, they still refer to themselves as lambda men. The first women's military sorority is Lambda Beta Alpha, and they even have a side organization for family members and ROTC cadets called the Orchids of Lambda. The letter Lambda has been adopted by militaries throughout Western history, largely because it was the symbol that was on the shield of the Spartans, not of all Greeks.