I was 5 and I decided to put my little sister (3) in a box and give it a good shove down the stairs.
She screamed all the way down until the box caught the last stair and flipped her out.
She cried and my father, the supervision for the day came running. She told on me; but not because I had shoved her down the stairs in a box — it was because I had done so without letting her adjust herself comfortably.
Kids are resilient; you could probably drop one out of a moving vehicle and they’d just bounce right on back.