If a murder occurs in a hotel room they don't have to advise every potential guest that that room was the scene of a murder so why would a cruise ship have to do any differently? If a fatal wreck occurs in a particular stretch of road, they don't stop traffic except for the time to clean up--within a few hours it's whizzing by as usual.
I'm sure we have all stayed in hotels,condos, apts. ship cabins, etc where something occurred that we never knew about. Better not to know.