I've read and re-read the part that embarassed you. And to be honest, I don't think you should have been embarassed about this:

"I see an employee approaching with my 8 yr old son. I started getting up to see what the problem was, but instead she just loudly explained to me from the other side that my son was not causing any problems, they just ask that all children stay with their parents. "

Part of her "loud" explaination was that you son was not doing anything wrong. I would guess that when she saw you get up, she decided to explain to you right away, so you wouldn't worry in the moments preceeding her catching up to you. I know if I saw one of my kids with a store employee, I would want to know IMMEDIATELY what was going on. And since your son didn't do anything wrong, she probably wasn't thinking you were going to get embarassed by something so benign.