The answer, which surprised me, was no - at least not institutionally (according to a friend who was in the coast guard for a time.) Turns out 90% of the work of the coast guard ends up being search and rescue type stuff, and they all know that this sort of thing is exactly what they signed up for and appreciate getting to "do" something instead of just patrolling.
http://en.wikipedia.org/wiki/Law_of_salvage
However, this article uses the recent example of the Carnival cruise rescue to give some very good arguments why the Coast Guard is so reluctant to charge.
http://gcaptain.com/cost-rescue/
(Note that Carnival has not charged for using their cruise ships to pick people up in the past.)
There are no corresponding rules for rendering assistance to people on land, so I'm not sure the NP comparison is valid.
I definitely had the impression that, like the article you linked, there was a "maritime tradition that holds that the duty to render assistance at sea to those in need is a universal obligation of the entire maritime community". Maybe they can try to recoup their costs later, but that was not my (uninformed) impression. Or maybe things are different in national vs international waters?
It's not lawless - it's just confusing because different vessels are held to different laws.
http://www.jstor.org/discover/10.2307/1288377?sid=2110519172...
The only thing thing I can't rule out for sure is that government salvors are somehow not entitled to compensation in international law even when private salvors are, but that would be pretty weird. In any case, it's definitely not true of "the entire maritime community".
For someone in a bad enough situation that they are willing to commit insurance fraud by faking a crash, it probably is a pretty good risk.
See this earlier comment for a link to data on small plane ditching: https://news.ycombinator.com/item?id=8957313
That said, insurance companies aren't stupid. Would they really let the person insure the plane for so much that it is better to lose it for insurance than to simply sell it?
These are not unsurvivable forces we're talking about.
For example, to ship a new Cirrus SR20 to Australia starts at $28,995 and you'll need to wait for factory reassembly and certification. To ferry the same aircraft costs $22,800.
I'd imagine a strong enough headwind would burn through your fuel pretty quickly.
Edit: This story is about someone flying from Hawaii to California where the flight ended up taking 4 hours longer than expected due to unexpected headwind. Luckily for him, he was in an airplane with extremely long range and had planned to fly directly to Oshkosh, WI! http://www.ez.org/t/cp34-p3