NLRA

Let's talk NLRA for a moment.  There appears to be some lingering confusion.

The federal National Labor Relations Act governs the rights and responsibilities of unions and private employers.  Excluded, with some exceptions, are public employees, independent contractors, employees of Federal, state or local government, etc. 

An employee doesn't have to be a member of a union to be protected under the NLRA as it protects the rights of employees to engage in "concerted activity."   "Concerted activity" takes place when two or more employees take action for their "mutual aid or protection regarding terms and conditions of employment."  This protection can extend to work-related conversations conducted on social media such as Facebook and Twitter.

Many employers prohibit employees discussing compensation or wage levels in the workplace, often communicating that such information is confidential.  These same employers would be surprised to learn that this policy or practice would violate federal labor law.    The National Labor Relations Act contains a provision, Section 7 (29 U.S.C. § 157), that gives all employees the right to "engage in concerted activities", including the right to discuss their terms and conditions of employment with each other. Section 8(a)(1) of the NLRA (29 U.S.C. § 158(a)(1)) makes it an unfair labor practice for an employer to deny or limit the Section 7 rights of employees. Based upon those two provisions, the National Labor Relations Board (NLRB) has taken the position for decades now that employers may not prohibit employees from discussing their pay and benefits, and that any attempts to do so actually violate the NLRA.

A couple of tips:

1. You can't prohibit employees from discussing compensation or benefits, but you can prohibit them from holding such discussions during assigned work hours.
2. Clearly communicate that employees are protected in discussing their own pay as well as pay and benefits of secondary employees if information was obtained through ordinary conversation with the second party. 
3. If information was accessed in a manner that was restricted, such as access to confidential files or other off-limit information, the company can take steps to uphold confidentiality.