It has been my understanding that DAN coverage is limited to accidents, so it wouldn't cover illness. (Admittedly, I did not take the time to read the policy again before posting this comment.) The medical insurance I have through an employer may or may not cover events outside the US, as it may depend on how much of an emergency it is. So I have been buying separate travel medical coverage from GeoBlue.
As for trip cancellation and interruption, I haven't taken an expensive liveaboard in a while, but I would buy something, even if it didn't cover the events living4experiences mentioned. I think we have to realize that insurance simply does not cover every possible event. If you lose money due to the fault of the liveaboard operator, and the operator refuses to make you whole, your only option may be to pursue legal action against them, which may not be worth the effort. Some risks are just ours to bear if we want to do these kinds of dive trips, it seems.
As for trip cancellation and interruption, I haven't taken an expensive liveaboard in a while, but I would buy something, even if it didn't cover the events living4experiences mentioned. I think we have to realize that insurance simply does not cover every possible event. If you lose money due to the fault of the liveaboard operator, and the operator refuses to make you whole, your only option may be to pursue legal action against them, which may not be worth the effort. Some risks are just ours to bear if we want to do these kinds of dive trips, it seems.