You know that's what I initially thought too. From what I've seen I can't see her actually hitting the child. Maybe I haven't seen all of the video but what I could see was very inconclusive. I couldn't make out any actual hits to the child. It almost seemed like she was beating the car seat.
That being said. If she was beating the child, I hope someone finds her and opens a similar can of whoop-ass on this poor excuse for a mother.