"Uh, yeah? Why else would you be carrying that around?" He motioned to her sword with less grace than a wet banana on an iceberg. Seriously, who did she think she was fooling with that getup?
Barney knew how to distinguish a person pretty easily, even in his drunken state, if he did say so himself. And he would. Nothing got past him. No ma'am. "Who carries a toothpick on steroids? Samurais, that's who."