BDAttitude
If you are not happy you refuse to sign, and make it known why. Everywhere I have worked that raises a big red flag, and the fact that it has happened goes viral instantly. I have seen people overidden (for good reason, and only after an exhaustive 'off project' review) but I have never seen an unsafe (as opposed to bad) design pushed through by one individual against the collective opposition of a design team. Yes, at the limit you have to be prepared to resign. But you likely won't have to, and you have to be able to sleep at night.