This is how we do it also, Raver. But you would warn them at least once, I notice. And sticking a fork into an electrical socket is quite a bit different from allowing them to run across a busy freeway. The 'learn for oneself' method has to be age appropriate.
Children are actually motivated by the presence of *some* boundaries, as counterintuitive as that may sound. They become confident if they feel 'safe' to learn.