Not quite following it either.

This year was the first year we took out third party no excess insurance for around £2 a day compared to Hertz supercover which costs over £15 a day.
Had a right palaver when picking the car up at GLA with the agent refusing to believe our policy was a no excess one despite me telling her I had read through all the t&c's of it several times. She went on to tell us that there would be a charge if we returned it with so much as a scratch on it. We would then have to claim the money back through the insurance company therefore it would be much easier to take out the Hertz policy.
I told her I already knew all this but she kept insisting that our policy was not as good as theirs and we should take out another one .....great way to start a driving holiday I thought.
We still had a temporary hold charge put on the card though....around £250 I think.