Actually, no cruise line likes to sail with an empty cabin. The reason is that they lose the opportunities for on-board revenue and the income for their employees.
Think about it. The food is already on the ship, the employees are there expecting to earn their tips, the bars are ready to serve drinks, the stores open...an empty cabin represents the loss of considerable income to a cruise line. During the first quarter of 2003 (the Iraq war) CLIA member cruise lines operated at 103% occupancy. Why? Because if they did not fill the cabins they would have dis-satisfied employees, food spoilage and lost revenues from shore excursions, photo revenue, spa revenues, casino, liquor and on and on.