I booked a car for 2 weeks in Burbank in August using an entertainment coupon with a 2 car upgrade for $392. I called the car rental place directly in Burbank to ask a question and the employee said I'm not guaranteed to get the car I am expecting when I arrive. He said the upgrade is only given if the cars are available. Has anyone ever used these coupons and then not gotten the desired car upon arrival? I haven't rented a car in years-we always use ME, any advice on getting a guaranteed car for cheaper?