Well you know what happen when you ass,u,me
If a guy showed up with no plane and asked to fly one of mine,, I'd give him directions to the Hobby Shop.
Now If I just happend to have my kids trainer/ buddy box with me I'd take him up, but he isn't going to just free load off my nitro all day.
I think the more resonable assumtion of the OP is that a guy shows up with his own equiptment.
You still haven't explained how you're going to qualify someone, Via a "Check Spin" or what ever you want to call it without a plane going up with him at the controls. Are you going to take your plane up 3-4 mistakes high and hand him the Tx??