We are discussing CEOs of startups and their negotiation with professional investors. In that scenerio, I cannot imagine a reason why a VC should give up something in the negotiation because he feels like the startup doesn't know what they are worth. Both sides have lawyers and advisors and the CEO is an adult who can analyze his future as well as anyone else.

If the CEO is unable to negotiate what they are worth, they should hire a dreaded MBA to help them.