He Had the Right
Since the boy was taking up more space than he should have been, then the mystery man had the right to sit directly on his legs. It was not about just the seat, but also about teaching the boy a lesson in manners, which his mother had clearly failed to do.
The Blame Game
Crazily enough, the mother didn’t even realize that the man had sat on her son’s legs! She was so distracted by her phone, she didn’t realize what was going on. However, once the man got up off the boy’s legs, she did realize that they had missed their stop, and she blamed this on her son.