On Wednesday, the Labor Department released a final version of the rule that will require employers to disclose if they hired a consultant to dissuade workers from joining a union. This rule will be implemented on all agreements made after July 1st. The Department of Labor has decided to implement this law so that workers are aware if there is someone who is trying to influence them when they are planning to organize.
See "Rule to Require Employers to Disclose Use of Anti-Union Consultants", NOAM SCHEIBER, The New York Times, March 23, 2016