Nothing in this Act shall be deemed to interfere with, impede, or in any way diminish the right of employees to bargain collectively with their employers through representatives of their own choosing in order to establish wages or other conditions of work in excess of the applicable minimum standards of the provisions of this Act. Nothing in this Act shall be deemed to affect the validity or change the terms of bona fide collective bargaining agreements in force on the effective date of this Act. After the effective date of this Act, requirements of this Act may be waived in a bona fide collective bargaining agreement, but only if the waiver is set forth explicitly in such agreement in clear and unambiguous terms.