MARPOL makes a strict liability offence of a pollution event in the Coastal State's waters and, by the same token, gives the Master a due diligence defence, which need only be proved on the civil burden of the balance of probabilities that they could not reasonably have done more in the discharge of their Flag State duties. Even if that were established, UNCLOS provides for monetary penalties only for a pollution offence except in the case of a wilful and serious act of pollution in the territorial sea – again, hardly an issue to conducting when the Master is exercising their Flag State duties. But tensions between Flag States and Port States have arisen due to the conflicting agendas which define their social priorities, and the seafarer gets caught between them. No better example can be found than that of the case of the Master and Mate of the Hebei Spirit.