Yeah. But that's not supposed to happen. Theoretically, you're supposed to look after your Navigator, so that he doesn't tell his House and his House doesn't reneg their contract. Theoretically, if you push your Navigator to the point to their refusal to Navigate, you're SooL.
How far can you push your Navigator? They're people, too. And usually whiny babies, 'cause they're also well aware of their importance.