"Don't confuse 'strict confidentiality' with 'keeping employees in the dark.' Private is useful. Secretive is deceptive." Stacy Feiner - from her book Talent Mindset.
Imagine this scenario faced by many employers with exiting employees: the employer gives the exiting employee the option to contractually waive any future right to sue the employer in exchange for a lump sum, a golden (or silver) parachute. The employee has signed the severance agreement, cashed the check, and that chapter of the company's life is closed.