I can, in sci-fi sense, imagine a world where we wouldn't need to discipline children, but it would take some pretty fundamental changes in our understanding of parenting techniques and probably involve some technology that doesn't exist today. That puts it pretty far away from "stop beating your wife" which just required you to... stop beating your wife. Are you thinking disciplining children instead would be a simple shift from today?

Also, would some acts, like murder, still be punishable? Or are you imagining a shift so deep that no one would need to be punished.