Just tried booking Hilton garden inn Waikiki around Xmas time and both the Aaa and best available rate wanted full prepayment?? And there was a 21 day cancellation policy?

Is this new for Hilton? Or just a "perk" for Xmas travel.

Ive booked hiltons in Hawaii - both paid and reward stays - over the past 5 years and have never seen these booking requirements.