Yes it does happen and has happened many times to every cruiseline. Sometimes there is considerable compensation and other times there is not. It depends on what happened, how much it interperred with the cruise, the state of the cruise industry at the time it happened, etc. We have missed ports and sometimes received nothing and sometimes recieved $25pp for the port we missed. These were all weather related for us and we just accepted that the Cruiseline was doing this in the best interest of safety and were very happy when they announced the $25pp to our account.