I work for life with every dog I own so that no matter what idiot runs up they will be ok. However--IF they are attacked by untrained children or adults--they are very thoroughly defended by me. In this case, I am with those who said they would have rebuttled the stupid woman's remark with one about her untrained children. My dogs know they will be protected by me--they also know they can step in to help if I require it, but only if I require it. I know most dogs are not trained to that degree, and I agree that most people are not either. I try to encourage calm interaction between people and my dogs on a daily basis--I repeat, CALM.
Soon I will be getting a new pup, who will be small and cute. He will gets lots of socialization, but much of it will be with my 90 lb ridgeback at his side, which tends to help with idiots.