It was a 4 hour flight and the little boy (probably around 3) across the aisle kept kicking the seat in front of him. His mom kept saying "Brayden, stop it", but he continued, and she apologized to the lady ahead of him once after she turned around and looked to see who was kicking her. Mom couldn't put him in her lap since she was holding a small baby.
Eventually after about 40 minutes, the lady in front of him (she was 20-something, flying alone) turned around, stood up and said "could you please stop that?"
Justified in speaking directly to the child, since his mother's efforts weren't working and she had already given her a "look"? Or should she have left it alone and let the mother continue to try to deal with it?