Provides that it is an unfair practice for an employer to fail or refuse to hire an individual, discharge or bar a person from employment, or discriminate against a person in compensation or in other terms or conditions of employment, because the employee or prospective employee participates in or has participated in an activity in furtherance of the exercise of the employee's constitutional rights of free speech and peaceful assembly, or other rights guaranteed by the first amendment of the United States Constitution, if the activity occurs off the premises of the employer during nonworking hours.