Another voice chiming in to agree that letting them watch you is not enough even if they follow along in the documentation, take notes, and sign off. They have to do it themselves first under your supervision, and then with you hands-off but available for questions.
You may know the saying, I hear I forget. I see I remember. I do I understand. I would be quite capable watching my trainer do something, and signing off that Ive been trained, but when I came to do it myself I would realize that I had not captured some essential elements and I would still have gaps in my knowledge.