It is not possible to rent a car in Europe without the rental company blocking from $500 to $1500 (approximate numbers) on the renter's credit card. If the car is returned with an empty fuel tank, for example, the rental company wants to be assured of a source of funds to pay the additional charge due at the end of the rental. Nothing is charged to the renter's credit card but the block has the effect of reducing the card's credit limit by the amount of the block.