I was laid off in September, 2016 and was I was well over the age of 50 as were just about everybody else knew that was laid off. To get our severance package we had to sign an agreement essentially giving up all rights to sue Cisco, etc. Cisco would not reveal the ages and other information regarding the profiles of people laid off until the agreement was signed.
I'm not a lawyer, but if enough people banded together to prove age discrimination, wouldn't these NDAs become void?