“Virtual certainty” would include:
Golfer hits ball over hill, players find abnormal course conditions in the line the ball travelled. After searching for the ball and not finding it you could claim it has to be in the abnormal condition and if all players agree it becomes a virtual certainty.
Here are a few others I disagree with. Range finders with slope mode that allow the slope mode to be turned off, trusting the golfer to use it only in “non-slope” mode. Before anyone jumps on me about bashing the integrity of golf and golfers, I played over 30 tournaments last year and at least ten times I found someone using a range finder with slope.
Now back to virtual certainty; a ball is hit into an area with a heavy marsh area that is NOT staked, directly next to an area of water (penalty area) that is staked. No one was able to see where the ball landed. It could have landed in the trouble area (water) or could be “lost” in the marsh area. after looking do you have a lost ball (in the marsh area) or a ball in the penalty area and how do you proceed?