I guess that your club allows non-members to fly aircraft at the field? At ours we (to the best of our abilities) enforce the members only rule as much as possible. Seeing as how the owner of the land our club is on 'lets' us fly there, any incident involving a member or non-member could result in us losing our field. Regardless, you did all that you can do. We have had people like that come to our field who simply do not understand that it is virtously impossible to pilot an aircraft with no prior experience. I have the PZ P-51 and it flies great for a small electric. It is $175 bucks, so I am boggled as how the father imagined it would not get destroyed immediately.