I'm not a direct shareholder, but if the Deleware court gives me an option not to pay $55 Billion that I thought was committed, I'd strongly consider.
What are the implications of not approving? On the plus side, the company keeps the compensation. On the minus side, Musk will be upset; and there's a trust issue for future compensation. On the neutral side, those receiving future compensation will endeavour to follow an approval process that is likely to stand up in court.