That can be a double edged sword, particularly when the lesson is about an edge case/pitfall. You'd be surprised how they can seemingly blunder their way to the

That can be a double edged sword, particularly when the lesson is about an edge case/pitfall. You'd be surprised how they can seemingly blunder their way to the solution while waltzing around the edge case, and thus not learning the intended lesson. Setting the stage where they either land in the pit, or start from within, ensures they're interacting with the material as intended.