Report from a student:
"Third, and most interestingly, I was able to use some of what you taught. About a week ago, my wife and I were walking our dogs at 22:00 around the neighborhood (where Alexandria and Arlington meet, so it's not exactly dangerous) and we turned a corner, to find two young male individuals hanging out on the sidewalk in 8-degree weather. There was a tire iron on the ground. I told my wife to be careful and keep the dogs close; as we got closer, one of the males picked up the tire iron, as they kept looking at us. At about 20 feet away, I unzipped my jacket and flapped it slightly open on my right hip (where my Glock 23 was holstered) -- the tire iron went back on the ground. As we walked by these two males, I made sure my jacket moved just enough, with my hand physically present, to display the Glock's grip -- they were silent and gave us space, without any threatening movements. Without your course, without carrying my firearm, or without knowing how to address the situation in a non-escalatory fashion, the outcome would have been extraordinarily different."
I'll call this one a win.