The notice below was posted adjusting rules at a golf club in Britain in 1940. You have to admit these guys really had to like the game to play!
German aircraft from Norway fly on missions to attack northern England. Because of the icy weather conditions, the barrels of their guns have a small dab of wax in the muzzle to protect them from clogging with ice.

In addition to attacking industrial or other targets close to golf courses, as they crossed the coast, they clear their guns by firing a few rounds at the golf courses.
Golfers were urged to take cover.