You also have a Dispatcher and a Load Controller, Load Controller does everything a dispatcher does but create the loading instruction theirselves for weight and balance along with the Loadsheet Dispatcher has their loadsheet and distribution created at mostly a central load control.
If a dispatcher or load controller is not satisfied that the a/c is safe for whatever reason, they can refuse to let the a/c go until they are satisifed and in that case we can tell the captain where to go, or where he's not going.
It is not just the captain that signs for the loadsheet it's the Dispatcher / Load controller too.