Interesting post for me as I found myself on the receiving end of situation similar to the one outlined.
My wife and I were shopping at a large upscale home improvement store a little too long for our two and a half year old. Nap time had come and gone by at least half an hour. The loss of a baloon to the ether triggered the predictable response - a belicose tyrant in complete berzerker meltdown. We made our way to the bathroom to try and calm our little one and succeded until she spied another childs baloon as we walked to the car.
The Berzerker returned.
As I was carrying her to our car (red faced, embarrassed and annoyed with myself for letting things get this far) an elderly lady inserted herself into the situation, asking if "everything was all right, becasue she was a teacher and knew that kind of crying and screaming meant something was wrong".
After counting to ten, turning four shades brighter red and taking a deep breath, I told her, "yes, our little one was going to be OK". I guess she didn't like the way I looked or something because she persisted. Isn't there something she could so, etc. Getting a little tired of her interjecting herself in our family matters, I explained that as a teacher she would probably remember that at this age children are constantly testing boundaries and control, hence tempertantrums and generally acting unsocially at times.
The lady backed off, I thanked her for her concern and then sat in the car with our little one as Mom calmed her down. That took another five minutes. The lady and her husband sat in their car the whole time.
I had several thoughts while sitting there. Could I have diffused the situation better (aside from not being there at the wrong time of day - very avoidable)? And... where the police on the way? As the area we were in is not CCW and very abritrary regarding knives, I wasn't looking forward to explaining my nominally legal folder. I was also thinking, I'm glad there are still people around that would take notice and ask as much as it embarrassed me. I would definitely inquire in some manner as well. Quite a day.
The unintended benefit was a shopping hiatus for a while.