Wow! You don't want to be inconvenienced if your friends experience some bad luck? Your cruise is more important than your friends? We have several sets of friends that we vacation with all the time, sometimes only one couple, sometimes 2 or 3, sometimes even as many as 5 or 6 other couples. We plan our vacations and if something comes up, we figure out the best way to handle it.
Maybe our friend circle is different than yours.