The number of females who unwittingly arrive on the shores of Cannazonia is not sufficient to satisfy the dietetic needs of the Cannazons who sail to the other islands to hunt for food.  They prefer to capture victims alive and take them back to their island for unspeakable rituals followed by the banquet.  Very few outsiders have ever been to Cannazonia and lived to tell about it.  Most contacts with Cannazons occur as they are taking their prey back to their boats for the fateful trip back to Cannazonia.   Any attempt to interfere would be tantamount to suicide.