I agree. My experience is get a foot in the door at the AD and all the lists open up. I patiently waited to get the Sub (first purchase), now I'm on the list for a Daytona and the SD43 - didn't even have to ask, just chatting to the managers. It perhaps helped me that I was wearing the watch they sold me on subsequent visits, so they know I'm an enthusiast and not flipping for profit.
The 'relationship' thing isn't total bollocks - in my experience the Rolex AD managers a) own several Rolex's and have a passion for horology, and b) actually like selling to people who they can have a decent conversation with.