"No risk, no reward"...
I think of Usher saying this to his team on "The Voice". (Yes, I love this show!) It may seem cliché, but it really should be the center of how we craft our lesson plans, or how we craft our craft as teachers. Teaching is a craft, not simply a schedule to be followed, it's a craft, an art, a constant evolution of trial, error, and listening.
Think of the child who is never allowed to climb a tree, eat sand, or simply fall down. What about the child who never asks a question, makes a prediction, designs her own approach to solve 12x345, or shares an emotional connection to a great piece of literature?
What happens when they become adults and have never taken a risk, and have always been told the "how" and the "why"?
Risk taking is essential; without an option to take risks there is little opportunity to learn. Critical thinking is starved, problem solving is void, communication is impossible.
Let them try, let them ask, let them fall.