Except that I know two instructors personally that are traumatized due to a student locking up during a stall and entering a spin. Just because you have never experienced it, does not mean it does not happen, and when it does, you really need to have some wits about you to know what to do. I could go on about several other situations that tend to send instructors to seek mental professionals, but we can focus on spins for now. BTW it will make you think twice about about instructing people that are physically stronger than you.