If you look at the small print you may, as well as getting hit for the deductibles, also get hit for a fraction of the hull value not covered by the FBO and also loss of (rental) income for the FBO if the a/c is totalled or down for any length of time. Check it carefully.
When I had an accident, my £120 renters' insurance saved me a bill for $5k for deductibles.
The renters' insurance paid up promptly and without a quibble.
I was very glad I'd spent that £120 (ish) and I'm not convinced that a kindly FBO would hold off on stiffing you for the deductibles these days.....
Cusco