A person may not seek to have an H-2A worker, a worker in corresponding employment, or a U.S. worker improperly rejected for employment or improperly laid off or displaced waive any rights conferred under 8 U.S.C. 1188, 20 CFR part 655, subpart B, or this part. Any agreement by a worker purporting to waive or modify any rights given to said person under 8 U.S.C. 1188, 20 CFR part 655, subpart B, or this part shall be void as contrary to public policy except as follows:

(a) Waivers or modifications of rights or obligations under 8 U.S.C. 1188, 20 CFR part 655, subpart B, or this part in favor of the Secretary shall be valid for purposes of enforcement; and

(b) Agreements in settlement of private litigation are permitted.