Communication is key. If silent bob had simply informed the budge that he was required byhis parents to investigate references/ feedback before payment, then maybe budgie would have accomodated him... or maybe not.
As it is, it sounds like eveything ended for the best, with budgie selling his marker, sb picking up a simpler gun, and loads of people vouching for budgie's integrity. After some awkward moments, everyone's better off, it seems to me.
If you need to verify someone is honest before doing business with them, be up front about it. Honesty is the best policy. Telling someone the deal is on, but you are really still checking out the person's history, you are yourself being a touch shady. If someone else is forcing you, you have every reason to inform the other party of the situation. Of course, they have every reason to sell to the first customer who can do business unrestricted, too.