I'm not judging the mom's morality. When guessing scenarios, I was looking at the realm of possibilities for the mom's embarassment only; just a list of possibilities. I'm usually pretty good at guessing human behavior since I've worked with the general public for sooooooooo long. You know, the good, the bad, the crazy, etc....
The confusing part of this story that would make anyone feel wierd is that we teach our children about 'stranger danger' but can't diminish their natural expectation of kindness and affection. What we feel is the FEAR of public scrutiny for showing affection to a child that we don't know. It is possible that that 'mix' of human conditions (kindness and fear) is what Boyd felt that made him feel funny about the whole thing.
Like I said before, had I been there, I would have seen a nice man helping a little boy out of the ball pit in a moment of kindness and nothing more....