Me: "Need help?"
Kid: "No, I just have a flat"
Me: "...Yeah, but do you want a hand?..."
Kid: "What would do you?"
Me: "Replace the tube... I have one right here" <-points to pannier
Kid: "Oh. No, that's ok. I need to get to school."
It was a very strange interaction, it left me trying to decide how he thought getting to school walking a flat tire would be any faster...
I think this case can be chalked up to "never talk to strangers"; he probably didn't feel safe with the situation. Similarly, most of the women riders I know prefer to call someone they know (if they can't fix their bike) rather than rely on the random stranger who comes along.