To be fair, I'm pretty sure NT would just say "Ok, no job for you, then. Next!" NT doesn't really have an Unathi Affirmative Action thing set up. They don't need to hire the lizards, it's just cheaper and more effective than humans.
They won't fire you for it, you just get fined out the ass and you won't get any preferential treatment if you refuse to sign it. It is optional, just in NT's own fucked up way.