Dints and scratches we can live with. It's broken springs, diffs, clutches etc that cause the problems.
And the idiots, as you saw, that gun it through mud and water. They then wonder why their engine won't run. We can tell straight away if it's a genuine mechanical problem or not, due to the amount of mud and water under the bonnet. They soon learn though when we just make them sit and wait while it all dries out. :D
I don't think borrowing one is an option, they are nearly always either in use, or being fixed. Plus I'd probably end up breaking one.