In NLRB v. Textile Workers, supra, and Machinists v. NLRB, 412 U.S. 84 (1973) (per curiam), the Court found as a corollary that unions may not fine former members who have resigned lawfully.
In Alvey v. General Electric Co., 622 F.2d 1279 (7th Cir. 1980), the Seventh Circuit found that the undemocratic effects of a regulation precluding laid-off employees from voting on a recall proposal outweighed union interests.