What is unsafe about adjusting the clevises on the plane? Easier to not adjust? When do you suggest that a beginner learns to adjust they plane? What is the instructor's role in this? This is part of what an instructor teaches students. We teach them how to safely make adjustments to the plane. If we don't teach them how are they supposed to learn to do it? When I teach a student I tell them what needs to be done, why it needs to be done, how it should be done, and then I help them do it. I let them do it themselves so that they learn to do it, but I am right there with them as they do it so that it is done correctly. And after they are finished I will inspect it to make sure it's correctly done. Instructing a student is more than just standing with them on the buddy box as they fly. It also includes things (but definitely not limited to) like teaching them to properly adjust and trim their plane. There is nothing unsafe about that all.

Ken