I got a written warning for using my employer's email system to send out a message to union members about an upcoming event. (A group of us are going to represent the union at an Earth Day festival, and one of the activities is going to be a rally against corporate practices that harm the environment.) My manager told me that I was being disciplined for using the company's email system for personal reasons or to solicit employees. But everyone sends personal email and email relating to The United Way, the Girl Scout cookie drive, and countless other causes, and the company just looks the other way. As far as I know, I'm the only employee who's been disciplined for breaking this rule; is it legal to selectively enforce company policies this way?
Enforcing a policy selectively such that only union-related activities are punished violates the National Labor Relations Act (NLRA). An employer may not single out communications relating to a union for discipline, whether they involve messages on t-shirts and other clothing expressing support for the union, social media posts about union issues, or email regarding union events. Selective enforcement against only union members or union discussions violates an employee's right to choose whether or not to support a union. Your shop steward or union rep will definitely be interested in your employer's decision to selective enforce its policy against your union-related message.
Currently, however, this rule applies only to discriminatory enforcement of a policy. In other words, if an employer allows employees to use email for personal reasons, but disciplines only employees who use it for union-related messages, that violates the NLRA. But if an employer bans all personal use of email and enforces that policy across the board, that does not violate the NLRA. It is the singling out of union messages for discipline that is illegal.
This may change, however. The National Labor Relations Board (NLRB) is considering a case that raises the issue of whether an employer policy banning all personal use of company email -- or all use of company email to solicit for outside groups -- violates the NLRA, even if it is enforced even-handedly.
Under the NLRA, employers must allow employees to talk about union matters during nonwork hours in nonwork areas (such as a locker room or lunch room). This rule is an effort to balance the employer's interest in running its business as it sees fit with the employees' interest in sharing information about the union in the one place where all of a company's workers are likely to gather: at work.
Some commentators have argued that email should be subject to the same rule: As long as employees send email during nonwork hours, they should be able to use the system to discuss union matters. So far, the NLRB has not extended this protection to use of the employer's email system. However, this could change as workplace standards and technologies evolve and the NLRB tries to make sure labor laws keep up with the times.