So when dealing with kids you're always going to have the occasional case where the parent gets pissed about what their kid did, and want to undo the entire transaction with regards to games they've traded in.  As a rule, Gord generally holds stuff from new kids he has never dealt with before for about a week just in case this happens.

"Yes, my son traded in 4 games that I want back."

"Which four games were those?"

"Pokemon Pinball, Red, Yellow, and Blue."

"Uhm…  Hang on.  According to the account, those were traded in way back in March.  And it's now October.  That's a touch long in wanting to resolve this issue."

"What are you saying?"

"Well, assuming I were to reverse the transaction, I don't have any copies of Pokemon Pinball in stock."

"Then you better get me a new one to replace it for free."

"Noooo….  That's quite alright.  If this was such a problem why did you wait six months?"

"It's your fault for dealing with my son!  Those weren't his games to trade."

"So it's my fault your son is an idiot… ok.  Good parenting there.  I bet you blame everyone for your problems, don't you?"

"You just replace those games!"

"Better idea, your son has $80 in credit on file.  He can use it to buy other games."

They then left, with the threat I had better replace the games.  Oddly enough, they never came back.  The $80 credit is still on file.