I don't want to sound like a killjoy but if things had gone badly wrong I wonder if the pilot would have expected his insurance policy to cover the claim?
There is a general insurance principle that an insured person should act at all times in the same way as if they were not insured. This is reflected in aircraft policies in a 'General Condition' which effectively says you should do all you can reasonably do to protect the insured item from loss. I'm not saying that a claim arising from this type of flying would definitely be refused but it does potentially raise a doubt!
Given what he was up to, the pilot would also do well to look at another condition which states the policy "shall not be construed as a policy of marine insurance."
