Are you asking about "show of force" or "lethal force?" It seems many people are talking about "lethal force."
AFAIK, "show of force" doesn't exist in my state. In IN, presenting a loaded weapon to someone is a Felony while presenting an unloaded gun is one step down to a high misdemeanor.
There's no reason to EVER "flash" your gun to someone. Either you need it and are correctly trained to draw, aim and fire when you need to or you don't need to use deadly force. If deadly force is not necessary, there is no reason to point your gun at anyone.