I'll bite on this one and just voice my opinion that some of the passengers I see cruising, I do not know if they are going to make it till sundown let alone till the end of the cruise.
I think you should bear and shoulder personal responsibility 100% yourself if you are fit to travel or not! In my opinion if you are not fit and too sick to travel, you shouldn't. Lest something that is NOT totally unforseeable happens to you and then you expect to get treatment on a cruiseship or elsewhere like you get at the Mayo Clinic!
If you are that sick, maybe you should entertain the thought of the WHAT IFs in light of the countries you are visiting and not expect the cruiseline to bail you out because you were heard-headed enough to travel.
I know this sounds harsh but in my opinion it is the reality of most medical emergencies onboard! I also think that cruiselines should wise up and get passengers, ALL passengers to sign waivers before they are allowed to board which indicate that they assume full personal responsibility for being healthy enough to travel.
Just my take on this subject!
Sorry for the long rant.