The Free City of Greyhawk
Near High Quarter
Cold clear day
While the party is minding their own business and simply strolling down the street, a merchant begins screaming in the PCs direction. He screams loud enough for anyone passing by to be able to hear: “You! Stop! Where is my 100 gp ya owe me!!”
As soon as he is confronted he easily realizes he was wrong and apologizes.
A little pressure by the party forces him to admit he was paid 5 gp by someone he’s never seen before to simply be part of a practical joke.
Any further pressure from any of the PCs is threatened by a calling of the guard.
There doesnt seem to be any reason to think he is lying