I checked into the Grand Wailea last year (Amex booking) and the agent showed me my reservation was booked through Priceline! I had booked a flight/hotel package because it priced out well and I prepaid the reservation, as required.

Also, every morning the hotel called me to tell me my credit card was declined, but I printed out my AMEX statement and showed them that I had already paid for my reservation weeks prior to arriving. It had nothing to do with incidentals or AMEX, so something was amiss - anyway, interesting to note where some of the inventory comes from.