I've carried for a long time. I have always practiced what I thought to be good situational awareness. I'm embarrassed to post this, but some may glean something useful from it, so here goes.
I stopped in to a local grocery store not long ago to pick up a few things while on the way home from somewhere (can't remember from where).
I was standing in a aisle ogling the micro-brews when the affable fellow walks up and engages me in a short conversation regarding the subject of my attention, laughs, then walks off. I didn't think anything of it at the time.
I purchase my few items and roll the basket out to the parking lot to my car and never noticed this same guy following behind me. I open the back of my Suburban, and while standing there with both hands full and with my left foot chocking the basket to hold it in place, this guy comes right up on me asking for money. I am standing there obviously caught flat-footed and wondering what to do while watching this guy to see where his hands were and basically trying to allow my brain to catch up with the situation.
Luckily, he only wanted a handout. He gave me a sob story and asked me to help him out. By then I had relaxed somewhat and told him that I didn't carry cash.... only a debit card (lie). He said OK, and got into the passenger seat of a brand new Toyota parked right beside me being driven my some women, who backed out and drove away with both of them laughing. I'm left standing there feeling very foolish and berating myself for having been caught in that manner. I was armed, with a concealed G19 tucked neatly away in an IWB.
The unnerving thing was that this guy had picked me out in the store. I have to assume that his banter with me was somehow his means of checking me out. The thing is, I don't look like a friendly guy.... really. And I'm not a 90 lb weakling, either. I was caught completely unawares! It could have turned out much worse. But, as it is, it serves as a learning experience.