Whenever we've rented a car in Florida and even in Europe for the past few years they've insisted on charging me for fuel at an inflated price and bring the car back empty. This is obviously designed to make them a bit more profit but like most people I cant' be bothered to argue about it. Still its not nearly as bad as the scam we couldnt'avoid when we used to book holidays in Florida through tour operators who would include "FREE" car hire in the price of the holiday you just had to pay for insurance which could total well over £200 a week for a very basic car.