It is very hard to seriously reprimand a small child for something if his mother cannot contain her laughter over the transgression.
"Dude. What are you doing? Don't spit."
"He was. Were you spitting?"
"Were you spitting? ...into the fan?"
Pause. Tiny nod from a small boy. Followed by a pathetic attempt at holding back surprised laughter from the small boy's amused-past-reason mother.
Way to show a united front, lady.
"I love boys," she gasps as I can do nothing but shake my head, thinking about the lesson he just walked away from this with. (Probably, correctly, that his mother is simply the damn best.)