Drive it like a rental

[RStar]

When I rent a car, I don't get their insurance, and with a $500 deductible on mine I'm responsible for the damage to at least that point. So I'm more carefull when renting.

That said, you made one point when you called it "Borrowing". My feeling is that when I borrow something, I want to return it in the same, or better condition than when I borrowed it. No matter if money changes hands as in a rental.