Seller's reaction @ closing table

[Jorge Caicedo]

A wholesaler friend of mine recently wholesaled a double for a cool $30k. When he went to the closing, w/ the end buyer and the title co. person said the amount that the buyer was picking it up for, the seller immediately got angry, looked at my friend and said..
" You mean he(the end buyer) is getting it for $40k when I signed the contract to this guy(my friend) for $10k?" anyway, the end buyer told the guy it was an assignment fee and the $10k was what he agreed upon. My question is: How do you guys handle this situation? I talked to a title co. that can wire the assignment fee to my checking acct. but if I had to go to the table, how is this handled? to be honest, i'd be a bit miffed if i was a seller who contracted at one price and it got sold for another..i don't plan on doing double closings btw.. any help is appreciated