I too have often wondered about these free cruises. My late husband and I had several HAL cruises and never had any offers or even upgrades. Since his passing and covid, I now cruise with a new partner, and he had only one cruise with HAL. We did two last fall and winter. To my surprise he got an offer by email last week, two pages of choices for free interior. We had a 10 day out of San Diego already booked for the end of November. We were able to cancel it,and book a 14 day Trans Atlantic. We upgraded to balcony, and purchased orange club . Scored a balcony on the corner of the bump out. All this for less than 1/2 of the 10 day we cancelled. 😊😊