From G.I. Joe: The Rise of Cobra
[handling an old iron mask
] This belongs to an ancestor of mine. He was caught selling arms to both sides. The French forced him to wear it for the rest of his life. They called him Destro, destroyer of nations.
So why do you keep it?
So that I never forget the most important rule in dealing arms.
Let me guess. Never sell to both sides?
Never get caught selling to both sides.