What is the chilling effect? Why is this a concern in labor relations?

In a
legal context, the chilling effect is the name given to the active discouragement of the
exercise of a legitimate right by the threat of legal sanction or prohibition. It is most often
used in relation to free speech. So, for instance, an individual or a corporation will threaten
to sue a newspaper or other media outlet if they publish certain information deemed detrimental
to the would-be plaintiff. Such threats are regarded as having a chilling effect on free speech,
as it discourages people from exercising their First Amendment rights.

The
chilling effect can also be observed in the field of labor relations. For instance, if a labor
union threatens to exercise its legitimate right to strike, then management will often go to
court to seek an injunction in order to prevent this from happening. Some companies also use a
variety of methods to discourage employees from forming labor unions.

It's
often the case that company rulebooks can have a chilling effect on workers' rights by
discouraging employees from engaging in practices such as collective bargaining. The National
Labor Relations Board (NLRB) has ruled such practices unlawful in cases such as
Lutheran Heritage Village-Livonia (2004). Even if the relevant provisions
of a rule book don't explicitly discourage or prohibit lawful activities by employees, they can
still be held unlawful if employees reasonably interpret them as having a chilling effect on
legitimate activities in the workplace.