In Florida Power Light Co. v. IBEW, Local 641, 417 U.S. 790, 804-05, 94 S.Ct. 2737, 2744-45, 41 L.Ed.2d 477 (1974), the Supreme Court held that no § 8(b)(1)(B) violation occurs unless the disciplined conduct adversely affects the performance of his or her § 8(b)(1)(B) duties.
In American Broadcasting Cos. v. Writers Guild, West, Inc., 437 U.S. 411 (1978) (ABC), the Court found that discipline imposed on grievance-handling supervisors who crossed union picket lines violated § 8(b)(1)(B), even though the supervisor-members did not adjust grievances for the striking employees, but only for employees whom the striking union did not represent or desire to represent.