I suppose, if he weren't a US flagged vessel.

I'm pretty sure, HE DIDN'T (effectively) HAVE ANY INSURANCE because I can't conceive an insurance company covering him. Regardless, getting recovery of damages isn't adequate relief.

I accept that the risks are remote because these sort of adventures, stunts, demonstrations, or whatever.

In this case, the question is what could any reasonable authority do in the circumstances when faced with the situaton -- i) US flagged vessel, ii) no ability to maintain even the illusion of watches, and iii) "trouble". It really would be reckless for anyone in command not to do what the CG did.

Moreover, if you decide to reckless risk your life, at what level does the remote possiblity that you might injure or kill others as a consequence become "acceptable"? If you decide to hike through Africa without a weapon to protect yourself, maybe we should asume that you'll cause dietary problems for the animals that might eat you. That might be reckless, but the consequences will likely be yours, and only yours, to bear.