^^^ why should he be? I fail to see why damage that is not your fault should affect you financially ... especially vandalism that is obviously not the hirer who did it (bit different to crash damage). That is what insurance is for, and should be the risk hire companies accept.
The risk of it being damaged in the carpark you were in, is the same as the risk when it is parked in their yard waiting to be rented. What would they do for hail, flood, fire, or any manner of other unforseen eventualities... yup, claim on insurance...... or write it off on tax as a loss.
If you hire an appliance from radio rentals and your house burns down do u pay? I bloody well doubt it.
If you rent a car and a hail storm damages every car in the city do they charge you? I really hope not...........
Tell them to nick off, if they don't like it then fly the single finger as you walk out and tell them to suck a fat one. To charge
you for the ****ups of another is so wrong