Wimp ideas, sirrah!

Bury a gas cylinder nearby, and run a hose to the bottom of the hole. Put in a trip-switch so that when a golf ball falls into the hole it is promptly returned on a jet of flame.

Or simply apply dual use: use golf courses as cemeteries and vice-versa. To have the ball land in the midst of a covey of mourners or fall into an open grave would give a whole new meaning to "play it where it lies." And sand traps wouldn't need sand anymore, either....

Or, still applying dual use, golf courses could also be used as archery or rifle ranges. It would give new meaning to "shooting some golf."