For thirty-two years, it has been a settled proposition that an employer may, upon the expiration of a contract, refuse to continue to negotiate with a “mixed-guard” union that represents its security guards. Continuing its long path of upsetting established precedent, on June 9, 2016, the National Labor Relations Board (“NLRB” or “Board”) reversed this and made clear that going forward a voluntary recognition of such a mixed-guard unit will require continued recognition just like…