What exactly does this mean - in order to sign in and search, you must sign an agreement. The sign-in agreement for the Mechanical Turk says it can debit my bank account??

BY REGISTERING FOR AND USING THE SITE, YOU CERTIFY THAT (1) YOU ARE AT LEAST 18 YEARS OLD;
(2) YOU HAVE THE AUTHORITY TO ENTER INTO THIS AGREEMENT AND BIND YOURSELF OR THE COMPANY
YOU REPRESENT; **(3) YOU AUTHORIZE THE ELECTRONIC TRANSFER OF FUNDS, AND IF YOU REQUEST
SERVICES, FOR AMAZON MECHANICAL TURK TO DEBIT YOUR BANK ACCOUNT IN ACCORDANCE
WITH SECTION 4 OF THIS PARTICIPATION AGREEMENT;** AND (4) YOU AGREE TO BE BOUND
BY ALL TERMS AND CONDITIONS OF THIS AGREEMENT, INCLUDING THE TERMS AND CONDITIONS
OF THE PAYMENT SERVICE DESCRIBED IN SECTION 4 AND ALL APPLICABLE POLICIES,
PROCEDURES AND GUIDELINES.