You take it out of the case it's been in all year, examine it, take a few practice shots to make sure it's good and then list it for sale (not eBay). You list it as in 'excellent condition'.
Someone buys the camera from you and pays cash. They leave, seemingly happy with the purchase.
The next day they call you and say that they noticed that it appears that the camera had been dropped and that the casing is about 1mm to 2mm out. They claim that they took it to a camera guy who says it would be $150 to repair.
They are asking for $100 of the sale price back.
You are not 100% convinced this injury exists on the camera or that it is worth that much to repair.
Do you refund the money or take another course of action?