Luckily I've never had to pull my weapon but have had to come close.
Background info: 34yo disabled veteran, dislocated both knees and 8 knee surgeries since. Have to use a cane now.
July 2011, me and my daughters were out geocaching and since I have to use a cane, I had my Walther PPS 9mm on me. We were out looking for a geocache for about 30 minutes when I noticed that a vagrant looking man had walked up. Individual looked like he was on drugs and was probably about a foot taller than me (I'm only 5'5"). Well I grab the girls and get them behind me and we start walking towards the car. The individual started walking towards us between us and the car. He started offering my daughters candy and I kept telling him to stop. Well after a few times of telling him to stop, he started walking straight towards me. I told the girls to get back to the car where my wife was since I now had the guys attention. He got about 7 yards from me and that's when I took a shooters stance and put my hand on my pistol, which was being carried in the small of my back.
It's amazing how quick a person will stop, after telling them three times before, once they see this simple stand and fight stance. Luckily, I didn't have to pull it and we continued on our way geocaching.