I have always put them away, except for once or twice (and I can't even remember why, there must have been a reason), tantrums or something. I've done it every time other than that once or twice, but I still just don't see why people are getting so upset about it. Don't get me wrong, like I said before it is annoying when they are left in the bays - but even then, it doesn't make me angry or anything.
Re the shopping bays, two of the centres here are good, one is bad. The one that is bad is the oldest one.
As to that poor woman - well that was enough to put the fear of god in me. I think it is totally acceptable to leave children in the car while paying for petrol as long as you can see them and you are in and out etc, but I can't bring myself to do it anymore after that. I just don't trust that that kind of thing won't happen to me. Ya know?