Being an adult
It’s not valid for kids to make their own decisions. He was still a young child who didn’t have the cognitive ability or maturity to differentiate between right and wrong. He would have embarrassed himself if it weren’t for his companion, but she didn’t seem too apologetic about the situation. Someone appeared to be with him, most likely his mother, since he was leaning up against her.
She could have stopped a crowd of people from congregating and looking for a place to sit down. Instead, she didn’t bat an eyelid as the youngster did his own thing. So much for being a responsible adult, she must have been aware that the kid was spread out all over the seat. She would have felt him leaning on her, so she could have given him some social etiquette training.