Most of my car rentals are from hertz and Avis, Mostly Hertzs for the last 10years. All my hiring had extra full cover for damaged which covers if your damaged the car etc, I just want to avoid paying for something if it was possible.
I have heard stories that those companies try to ripp you off, victimising customers for things about damaged done to the vehicle, could someone give me a heads up If I infact Ihave wasted money for the cover for all those years? It is quite expensive considering it costs around $1000 for 10days if not the what you call it excess would save $300.
I'm not sure I understand your question, but I've rented cars plenty of times, and I never take out that (exy) 'extra cover' they offer; just the standard cover. I do take a few pictures of the outside of the car before I get in it/drive it away though, particularly any wee scratches etc. there might be. Once one of the cars had some damage to the interior (small rip in the back-seat), so I asked the staffer serving me to snap a pic of it, print it out and sign/date it; just to be on the safe side. She was quite happy to do this/ seemed to think it was a perfectly logical request.
So maybe you might consider doing sommat like this, instead of getting that exy 'extra' insurance. You could just get the 'standard' insurance, but make sure you snap a pic of any pre-existing damage on your phone, and SMS the pic to the dealership on the spot, with the text/caption 'prior damage' (or something similar); they'll completely understand, I'm sure.