If you read the legalese portion of the Hertz website, it clearly states that reservations for specialty vehicles mean the customer is guaranteed to receive that specific type of vehicle. In other words, if you book a minivan, you get a minivan. If you book a large SUV, you get a large SUV. If you book a Corvette, you get a Corvette. The website states that the location must honor guaranteed rates. The website also reminds customers that reservations for standard cars may be subject to substitution of alternative equipment.