Paul, many years ago I took a friend up for a glider ride. I got him strapped in the back seat and then got into the front and started my preflight. The last thing I said to him was “don’t touch anything, and if you think I asked you to touch anything then ask me “are you sure?”
When I was ready to get off tow I told him to “grab the round yellow ball and pull it.”
He came back with “Are you sure?”
Preflight works!