I once rented a brand new Toyota Camry (with about 40km on the odometer) for a 2 week emergency job. Two of us had about 12 days to accomplish about 35 days work, all over Ontario and Quebec. We pretty much lived in the car for that period of time.
By the time we had returned it, we'd put about 4500km on it, filled the back seat knee deep with McDonalds wrappers, covered the car in mud, coal dust, and various other compounds, and riddled the front end of the car (particularly the engine hood) with little dimples, having parked just a little too close to where a Great Lakes bulk carrier (freighter) was unloading klinker pellets. In short, we trashed the car.
We also fully expected to get billed big time for the damage, which would then be passed on to our client (whose fault it was that we had to work in that fashion.) We pointed all this out to the rental agency when we returned it, but all we got was a shrug.
Never heard another thing about it.
(National at YYZ, in mid-1999 -- we were upgrading ships for Y2K to meet a psuedo-regulatory deadline.)