Booked, AND PAID for two nights at the Aria in Las Vegas for this Easter weekend. Arrived at the desk. They had no record of my reservation. I didn't have the printed confirmation... my fault. But why didn't Kayak process the booking? They hit my credit card... great... but they couldn't book the reservation. I'm out two nights, a ruined weekend. Am steamed. Will never use Kayak.com again.