This is the part most people skip, and it is the part that prevents the dispute rather than
winning it.
Walk round the vehicle with the customer. Point at the existing scratches out loud. Have
them acknowledge the fuel level and the odometer reading. Ten seconds of "as you can see, there
is already a mark here" removes almost all of the bad-faith arguments later, because the
customer knows you both saw it.
If they signed something that says the vehicle went out with a quarter tank, the conversation
about fuel on return is short.
