I’ve used these before. Spanish hire co charged me £700 for 'scratches' on a car hire. These paid out very quickly. You have to leave a deposit with the hire car co and if they charge you, you just claim it back after showing proof that you hired the car and paid the claim so make sure you keep the hire car paperwork. Make sure you take it out the day before your hire starts. Ie not today if you’re hiring it today.