The terms and conditions say:
Reservations for rentals or stays must be made between June 6, 2008 and August 31, 2008.
I have a Hilton reservation for Sunday that was made earlier this week. Do I need to rebook my room today to make this stay count for the promotion? I've already rebooked my rental car for the weekend, but would like to leave my hotel reservation intact because the price has increased. To the best of my recollection, with promotions such as these, WN usually only cares about when the activity takes place relative to the promotion period, not when the reservation or booking was made.