Let's get back to the base scenarios.
1: Doorbell & Mr. Nasty being abnoxious at my door. Perhaps pounding and kicking it. I won't display anything until he either approaches a window or manages to force the door. By that time, hopefully, my 1911 has covered my retreat to the bedroom to fetch the 12gauge. That is what I want him to see -- not me holding something like a .25 caliber mouse gun.
2: Parking lot intercept. I too have BTDT and got the T-shirt. Now I'll have to break with most opinions here and say something different.
Carrying in a public place does several things. But I think the most important one is that it allows you to look a potential perp in the eye with the look of the hunter, not the prey. I've noticed that when I'm carrying I tend to watch potential threats and look them in the eye more so that when I'm unarmed. This is tantamount to yelling "I see you, dirtbag, and I'm not letting my guard down!" and they can see it. I have no doubt that this alone has caused several losers to seek easier victims.
In a parking lot scenario, I'll change my direction to see if the perp also changes to intercept. At that stage, if he does, the body turns the strong side hip away from him, right foot back, knees flexed, hand starting the reach while the offhand starts low, palm out and rises with my voice commanding "Stay back!" If he continues to advance in a meanacing fashion, I'll likely move back just a tad before using him as a JHP test target.
BillCA in CA (Unfortunately)