Seems like point reservations should count too. The only criteria is the reservation is linked to your account and you have a credit card used for the reservation, which I believe is needed to pay some small portion of tax anyways for points redemptions.

Terms:

Ultimate Reservation Guarantee. To be eligible, Member's Loyalty Program Member Number and a valid credit card number must be included with the reservation. If a Participating Property is unable to honor the reservation, it will pay for comparable accommodation nearby for the Elite Member that night and compensate the Member for the inconvenience. A Participating Property must be open and operational for the Ultimate Reservation Guarantee benefit/compensation to apply. At The Ritz-Carlton® and St. Regis Hotels, the Ultimate Reservation Guarantee only applies to Titanium Elite and Ambassador Elite Members. The Ultimate Reservation Guarantee is offered at the following brands: The Ritz-Carlton®, St. Regis, EDITION®, The Luxury Collection, W Hotels, JW Marriott®, Marriott Hotels®, Sheraton, Delta Hotels®, Le Méridien, Westin, Autograph Collection® Hotels, Renaissance® Hotels, Tribute Portfolio, Gaylord Hotels®, Courtyard®, Four Points, SpringHill Suites®, Protea Hotels®, Fairfield by Marriott®, AC Hotels®, Aloft® Hotels, Moxy® Hotels, Residence Inn®, TownePlace Suites® and Element. The Ultimate Reservation Guarantee is not offered at the following brands: Design Hotels, Marriott Vacation Club, Marriott Grand Residence Club, and Vistana properties. Pursuant to section 4.1.c. if an Elite Member has a confirmed reservation, but is relocated from the property upon arrival, the Participating Property will pay the Ultimate Reservation Guarantee compensation in place on that date under the Program Rules. If an Elite Member receives Ultimate Reservation Guarantee compensation, then he/she is not eligible to receive additional Elite Benefits Guarantee compensation.