Curious... is there ever a time to draw, but not fire?
In the stories that I have read, where the presentation of a firearm causes the BG to reconsider their actions without actually firing a shot, typically two of the AOJ criteria were present, coupled with a disparity of force. In these situations, the danger was imminent and real and the BG, typically multiple, were in the process of following and setting up their mark, which they had incorrectly viewed as a safe target. In these instances, had they progressed much further, the situation would likely have required actual deadly force to resolve.
In my opinion, there is a distinct difference between brandishing and readying a firearm with the intent to use it. I also don't see a problem with letting a BG know that should they proceed that they will be met with lethal force, as this alone may stop the threat.