What’s stopping entity lawyers from expanding no-contact protection?

Under Niesig, No contact rule NCR applies to those with vicarious liability or implementing advice of counsel. MR 4.2 and comments

What’s stopping lawyers from giving every lower level employee who may have info detrimental to entity case from being protected under NCR by implementing advice?

I understand policy wise this would hinder litigation and discovery and be unfair/unreasonable to opposing counsel (IE blanket advice to every employee of entity) but is there controlling law, case that gives the limitations of expanding Niesig NCR? That third prong seems so broad! I’m going crazy here.