Indeed, the only truly serious questions are ones that even a child can formulate. Only the most naive of questions are truly serious. They are the questions with no answers. A question with no answer is a barrier that cannot be breached. In other words, it is questions with no answers that set the limit of human possibilities, describe the boundaries of human existence.
Now I've been criticized for advocating that people push their boundaries because sometimes people get caught. Sometimes people get fired. Sometimes people lose their jobs because of pushing the boundaries too far, but it's an interesting experience. They found they didn't want to stay within those limitations that they were pushing. Once people find they can survive outside the limits, they're much happier. They don't want to feel trapped. So I think we can urge people to push the boundaries as far as they can, and if they get in trouble, fine; that's not too bad if that's what they want to do.
Don't go overboard in praising required behavior: 'We have only done our duty' (Luke 17: 10). But do go overboard when your child confesses the truth, repents honestly, takes chances, and loves openly. Praise the developing character in your child as it emerges in active, loving, responsible behavior.
Training moments occur when both parents and children do their jobs. The parent's job is to make the rule. The child's job is to break the rule. The parent then corrects and disciplines. The child breaks the rule again, and the parent manages the consequences and empathy that then turn the rule into reality and internal structure for the child.