Doing that has a big chance of backfiring from a PR perspectives and I’d be surprised if a good lawyer couldn’t find an argument that the agreement did not extend to bad-faith claims or, depending on whether things like the WARN act apply, illegal acts. I would be surprised if they tried that because as soon as they sue, she’d be able to request a lot of information under discovery and the odds are pretty high that would reveal something which they’d like not to have public. Nuking a former employee with no assets is not worth the NLRB or similar getting interested.