A: What do you think of that decision of the boss to withhold John’s bonus?

    B: He meant it as a shot across the bows to all employees who might ask for a kickback from customers.

    Note: The bows refer to shoulders of a ship shaped in the form of a bow. The idiom derives from the naval practice of firing a cannon shot across the bows of an opponent’s ship to show them that you are prepared to do battle. The more general figurative use of the expression, just to mean a warning, is a 20th century innovation. For example, this piece from The Fresno Bee Republican, just prior to WWII, in August 1937: “When the situation in Central Europe becomes threatening in the eyes of the great public, ... the United States Government will fire the third warning shot across the bows.”