Had a wonderful session with Rebecca and her mastiff mix, Luke, whom we did one session with before. We discussed beforehand that we would act like strangers on a walk, and not talk to each other, and Rebecca would randomly come toward us, cross our path, or hide and walk/jog out into our path. Cai of course barked a couple of times the first time he saw Luke, but then he quickly settled down and was able to give me good attention. I was so proud of how he did!
He did so well, in fact, that I decided to try taking him into PetCo a couple of hours later. A pair of westies came in, and he saw them as they were moving in our direction, and he lost it. Lots of barking and straining at the end of the leash (and slipping on the smooth floor). I walked him around and he calmed down a bit, but then he caught sight of a pair of toy poodles (why all in pairs today?) and growled and lunged, so we left the store. That was disappointing. It's too hard in the store to get a sightline on another dog, from far away, and make sure they're not coming toward us.
I guess the next step is to try BAT in a store with a friend who will stay on the far side, while avoiding other customers as best I can. I will also continue our work at the local trailhead where I want to hike with him someday.