Framer - if a passenger spits at anyone, be they crew or passenger, then a criminal offence has been committed, whole different ball game. The offence is reported to police and it is now their problem. Chances are the pax will be arrested, cautioned and told he has to leave the aircraft, the police are within their remit to physically remove him if he doesn't obey a lawful order.
On Eyre - Not sure about this but I think the Harbour Master has considerable authority when the ship is still tied up.