If you are not sure what are shooting, why the heck would you shoot??? Rule #4 be sure of your target.

Very fair request,really common sense.I must admit that I did it a few times when I first started, but a pair of binoculars and the ability to pass on shots after dark:30 is all that is needed to avoid this mistake. If all you can see is the outline of a deer they need to learn to pass on those shots.