OK, I'll bite, what are those situations? Remember, this is about threatening someone with your gun and making demands that they're supposed to follow.
Ok, go.
If you draw your gun just to threaten somebody or to brandish without the intent to actually use it, you could be making a serious mistake. I think this is Rastoff's point, and it is well taken.
However, in a situation that involves drawing your gun, your intent should be to shoot
if necessary. There are steps that should be taken in between drawing and pulling the trigger. In the 1.5-3 seconds that it takes to draw from concealment and "point in", a threatening situation can change dramatically. You may not any longer be justified in shooting. The pull-the-trigger decision before even starting the draw can be a mistake.
Having a gun in your hand will almost always allow for a faster, more accurate first shot than having to draw from concealment. It is a tactical advantage to have your gun drawn if you're going to have to use it.
Issuing commands to a threat is a strategy taught by some schools of gun training. In a civilian sense I don't believe it is necessary or required. If you do decide to issue commands, gun in hand, which are not followed and you perceive a deadly threat then you're justified to shoot. The problem is whether you are
committed to shooting an adversary or only scaring him/them. When you draw you should be committed to shooting but have the presence of mind NOT to do so. Such fast decisions are very training dependent. There are certain "go or no go" signals your brain must process very quickly.
If I lived in a "duty to retreat state", I would probably want to draw my gun and have it ready for me while retreating, especially if covering others. I should be committed to using it if necessary if retreat does not stop the threat.
While not counting on this as a winning strategy, it is true in at least some cases that the mere presence of a firearm will deter an attack.
If someone is standing 20' from me with a bat, knife or machete, I would not wait to draw. I would even point in but not fire unless that individual ignored my deadly force threat by closing the gap. Many aggressors would not attack a gun in such a circumstance, but if he chose to, you are far ahead of having to draw from concealment. You also have more latitude and focus in decision making.
I do not believe you are required to shoot if you draw, but you should be able to do so if the circumstances warrant it. In the game of chicken depicted in the first photograph, the second to draw should have been holy.