Sure and anyone who has worked in a toxic workplace knows exactly what it means to require a direct path to leadership to resolve an issue instead of just resolving it.
True, they can't renegotiate agreements that don't yet exist.
However the fact that the corporate leadership could even make those threats to not-yet-departed employees indicates that something is already broken or missing in the legal relationship with current ones.
A simple example might for the company to clearly state in their handbook--for all current employees--that vested shares cannot be clawed back.
