Sometimes.
From hilton.com:
- Guaranteed reservations availability, subject to the restrictions stated herein, at hotels within the Hilton Portfolio when paid reservations are made before midnight hotel local time, two or more days (48 hours) prior to intended arrival. RESTRICTIONS: This guarantee does not apply to reservations paid for in part or in full by Hilton Honors Points, or free night certificates issued by Hilton. This guarantee does not apply to a hotel when that hotel becomes overbooked on inventory by 10% or more (meaning, 110% or more of rooms are reserved). For certain hotels within the Hilton Portfolio, this guarantee does not apply when that hotel becomes overbooked on inventory by 2% or more (meaning, 102% or more of rooms are reserved). Consult with the individual hotel or view hotels with the 2% cap to determine whether the 2% limitation applies. This guarantee also does not apply to any hotel during Extraordinary Demand Dates. The term "Extraordinary Demand Dates" are dates determined by the hotel and Hilton Honors, in their sole discretion, that are consistently popular reservation dates for guests, such as during major events in the area or New Year's Eve. This guarantee applies to only one room reserved with a valid credit card and occupied by the Diamond Elite Member. Please note that this guarantee does not impact the rate, and the reservations made under the guarantee will be subject to the hotel's prevailing rate for the accommodations requested. In the event the Member does not arrive as scheduled, or does not call to cancel and obtain a cancellation number, the credit card will be charged one night's room and tax. The 48-Hour Reservations Guarantee applies to reservations made online at a hotel Website, through Hilton Reservations and Customer Care, through the Diamond Special Services Department, or with the hotel directly. Promotional Rewards are not applicable for reservations booked under the 48-Hour Reservations Guarantee. The 48-Hour Reservations Guarantee may periodically be restricted in Homewood Suites by Hilton and Home2 Suites by Hilton hotels due to the extended stay nature of guest stays at the Homewood Suites by Hilton and Home2 Suites by Hilton brands. The 48 hour guarantee does not apply at the Conrad Maldives Resort & Spa, Hilton Seychelles Northolme Resort and Spa, Ho'olei at Grand Wailea, Kingston Plantation Condos, Royale Palms, Conrad Koh Samui Resort & Spa or Hilton Grand Vacation.
Take special note of the restrictions, especially if there is a special event or if the hotel is overbooked by 2% then it does not apply. And review these threads:
https://www.flyertalk.com/forum/hilt...rvation-4.html
https://www.flyertalk.com/forum/hilt...ill-thing.html
Diamond force no more?
https://www.flyertalk.com/forum/hilt...guarantee.html