In the jokers circumstance, and others like it,  of not knowing how long he will be there, why not charge him a usage fee of $10 or so every time he flies?  The field gets it's precious money, joker gets to fly without any long term $150, $200, $300 obligation and everyone is happy.  If there is any question as to whether or not this person (the joker or anybody else) can fly, put them on a good sim with a few scenarios and make them prove that they have a reasonable handle on things.  Then you make them successfully solo at the field, smile, shake there hand and say thank you for supporting this hobby and the AMA that'll be $10. Hope to see you again soon. That's $10 more that the club wouldn't have had before.....instead of not allowing them to fly.</p>