Is it unfair labor practice for an individual employer to voluntarily recognize a union which does not enjoy majority support?

6 In the formation of multi-employer units, it is an unfair labor practice for an individual employer to voluntarily recognize a union which does not enjoy majority support among that employer's employees. Thus when employers join a multi-employer unit and recognize the union, they are viewed as implicitly declaring that the majority of their employees favor the union. Subsequent withdrawal from the multi-employer unit simply entails a reversion to the original unit, a unit previously determined from the employer's own conduct to favor the union's representation. NLRB v. Tahoe Nugget at 303.

7 Respondents correctly quoted a passage from Celanese which states that: