In NLRB v. Rybold Heater Co., 408 F.2d 888, 891 (6th Cir. 1969), the court enforced a Board order to cease and desist from photographing or pretending to photograph protected activity.
In National Labor Relations Board v. Simplex Time Recorder Company, 1 Cir., 401 F.2d 547, 549, the court said that creating an impression of surveillance "means wilful conduct and a justifiable impression."