I am with the cruise line on this one. Can you imagine the chaos if their policy were any different? I believe that it’s the rigidity of the policy that inspires fear in its passengers and motivates everybody to get back on time.
100% with the cruise line, cruise ships have like what 2000 passengers and 1000 crew? if 8 people are not back on time, the remaining 2992 people on board should not be disadvantaged because of it. They're all like "why aren't the cruise line thinking of us", my question to them is, "why aren't you thinking of the all the other people on board"
Charter a private yacht. I've done it for clients and they determine where, when and usually how-- unless weather or other conditions supersede-- you can "explore" areas on your journey.. As for costs being higher for Cruise Line provided versus "others" -- you're throwing the dice and relying on comments "given" on their sites which might not even be from real people but from a machine. Personally and professionally I would not make plans away from those of the Cruise Line's at that destination or any other with no town or city nearby in case of emergency. Your on site "guide" may be able to give the same presentation in English but not be able to understand or get immediate help for someone with a medical or other need. As was said by Dorothy in the Wiz, "We're not in Kansas any more!" applies to travel to unique areas that sound great except when they're not.