First of all, awesome thread! Thanks for starting it and posting so much info here.
What's tough, though, is that there are just so many variables. On the one hand, my instinct is to agree with Irish - if a BG has a gun and seems willing to use it, I don't want to put myself or anyone else in any more danger than necessary. So it follows that I'll shoot if I can, or haul out of there if that seems more prudent. But then I play the "what if" game, and I can come up with a lot of scenarios about things that weren't discussed in the article, where I might be comfortable giving the robbers that warning sign. Where giving that warning sign not only wouldn't add to my or anyone else's danger, but would maybe even give some innocent bystanders an opportunity to clear out of my line of fire or etc.
That's what's tough (to me) about analyzing these stories. They're super-useful, and please keep them coming! But the stories (even the ones with video) often just don't have enough information to support a thorough analysis of the tactics.
Maybe someone with more experience analyzing this sort of thing can share tips for getting the most learning out of these stories....?