In the US, even in right-to-work states, employees are guaranteed certain protections, under Federal Law. Employers often use tactics to circumvent those protections. In many instances, employees have secretly recorded these violations. While it may be against a corporations policy, and can lead to termination of employment, if you have recorded that violation, it is often still admissable evidence and can lead to financial compensation and judgement.
Corporations in right-to-work states, and specifically non-unionized places of employment and industries, often violate employees rights in the US. An audio recording is often a wronged employees only legal recourse.