Hi,
I believe this is why there is a law suit in New Jersey vs. RCI (see topic below). They re-routed a cruise from Bermuda to Canada without telling the passengers they were doing so until they were on board and ruined everyone's vacations, including that of a couple who were planning on getting married in Bermuda. The cruise contract says that, basically, they can do whatever they want to keep the ship/passengers out of danger, but this was pretty extreme. The moral is....bring layers just in case!