On the last cruise ship I was on, the wait staff and cabin cleaning crews had many muzzies. How hard would it be for them to screw up the works? I better not say any more. It might give people ideas.
Fortunately, I guess, I have never been inclined to want to go on cruise. The last time one of my daughters and her husband went on one, nearly the entire passenger list was down with a bug during the entire Cruise!
Muslim terrorists infiltrated and hijacked the Italian cruise ship Achille Lauro in 1985, killing Jewish passenger Leon Klinghoffer.