@LotsOfZeros:
I can see why you do take the kayak search -> direct buy route. Also, I've found that orbitz sometimes even offers cheaper rates than the airlines themselves. god knows why.
I used Orbitz quite a bit several years ago. As I understand, they were formed as a joint venture by several airlines in response to competition they were getting from Expedia and Travelocity so your experience may possibly be due to some reserved blocks of seats as part of their collective agreement.
If you like to go for risky stuff, just book hotels online on the same day of your check-in. I managed to get an executive double room in NYC at some 4* hotel in midtown for $100 a night in november... and even tho the staff were a piece of shit, the room and the hotel itself was awesome.
This will often work much in the way I described some plane tickets where the prices sometimes drop near the travel date in response to lagging sales. It's a risk if you don't have good intel on your destination (ie: you didn't know about that big street mimes convention this weekend, etc).
The main reason I rarely use this method with hotels is due to the nature of my travel involves visiting my software customers and is typically already booked so I rarely need to take these types of travel risks personally.
.... damn, we could all write a clickbank ebook on this!