Demons, find the various proposals and to order everything. Of course, the car rental companies (and their tenant counterparts) would prefer not to do so. The threat does not show the customers who bought a car in advance, but do not cancel your reservation, if you change your plans, making it difficult for companies to hire, to match your inventory with their clients. That is why many companies offer discounts to customers who pay in advance, as they are less likely to cancel without bail.