You may be asked to guarantee your booking with a debit/credit card. The Pre-Authorization hold is not a charge and no funds would be debited from your account; however, your bank statement may show this operation as a pending transaction. When you are asked to provide your credit/debit card, it is for this purpose; the Pre-Authorization serves as a guarantee of the availability of funds necessary to cover for any possible charges worth up to the cost of the first night of your reservation.