Last month was my son's school chorus concert. Obviously, just about everyone there was taking pictures and/or video, but every camera I saw was either a cell phone or a point and shoot they just held up while sitting. I was the only one with a DSLR, and at first I felt kind of weird about being the only parent that was moving around to get the right shots. When I realized that no one gave a damn what I was doing, because they were busy watching their children, it helped me relax. What made me relax even more was that one of my pictures got published in our local newspaper.
As far as stopping along the road to take a shot or two, I haven't tried that as of yet, but I don't think I'd have too much of a problem with it. I've seen other people doing it and never gave it a second thought.
Asking strangers is probably where I'd be the most shy. I don't know if I could do that!