Five hotels in Hawaii that fly the Sheraton flag have recently been sold by their Japanese owners. The new owner might put the properties--the Sheraton Maui and four Honolulu properties (the Royal Hawaiian, Moana Surfrider, the Princess Kaiulani and the Sheraton Waikiki)--in the hands of several hotel-management firms. That would seriously dilute the value of Starwood Preferred Guest points in Hawaii.