I doubt the govt wouldnt have some sort of way of getting the coin out of you. I saw a boat on boatpoint a while back that had been imported but the owners hadnt paid thier dues. I am sure many people ran away from it once they read that parragraph from the broker- ultimately devaluing the boat .
Remember that if you by and american made boat ( and can prove it with documentation) there is no duty, due to a trade
agreement with the yanks. But if you buy a frog boat, you have to cough up that bit extra. You may want to double check that Rudd/Gillard didnt change it. But it has been the rule
of thumb for some time