I think you did the right thing, jb. If your W had seen you, she could have wrongly assumed you were following her, or checking up on her. I can't imagine that would have gone over well.
Anyway, I wouldn't read too much into it at this point.
She could have simply run into a friend so perhaps they were chatting in the van to get out of the rain. I wouldn't let your imagination run wild because meeting in a Lowe's parking lot does not exactly seem like a good date spot.
Thanks, E. This along with KD's post really helped me out tonight. Especially your comment at the end punctuated with my old friend the crazy smiley. I didn't really expect to see my W's car in the parking lot. It was kind of like, "Oh crap, that IS her car, I'm outta here!!" , despite my S trying to encourage me to find her in the store and give her a ride to her car.
There's a lot of ifs. That may or may not have been her in the van. If it was her in the van, I don't know what the circumstances were. If it was her in the van, and it was a OM, I am just going to keep doing what I'm doing and be the better option - so back to GAL'ing. Her loss. If it was her and she saw me, it could be her guilt to deal with. But then you're right - she could also think I was checking up on her, and that wouldn't be a good thing.