Purportedly posted at a north Yorkshire golf club during the Blitz, and a prime example of (a) the British stiff upper lip, and/or (b) the overwhelming pettiness of golf and/ or (c) some club wag taking the piss. Still.
German aircraft from Norway would fly on missions to northern England; because of the icy weather conditions, the barrels of their guns had a small dab of wax to protect them. As they crossed the coast, they would clear their guns by firing a few rounds at the golf courses. Golfers were urged to take cover.