Hi! I've been doing a lot reading on the Hyatt site the last couple of weeks--thanks to everyone for the great info. I'm currently Gold, soon to be Plat, then I want to register for the diamond challenge (15 nights in 180 days). My belief is that you can't book phantom nights at Hyatt (i.e., find a cheap rate and never check in, but get the credit). My question is, if I book a good rate at a HP and check in, do I have to physically check out the next day? If I'm not at the property the next day, what would you recommend--would a phone call suffice? Does anyone else have experience doing this?