What they have to do first, with your permission - and they definitely stress it three or four times - is deactivate the Google I/O demo account, and then once the ESN is clear, they'll move it over to your account. But since the device is not out and the "codes are not in the system quite yet", they take their sweet time in trying to figure out just how to swap the ESN. In my eyes, theoretically, I could've just gone to sprint.com/activate and done it myself, but the EVO needs to have that clear ESN first, which is why I called them - plus I had to re-activate an old Sprint account I had.
Similarly, when Verizon gave us the free Droids, I had to swap the ESN on that one - and Verizon had the same damned problem cancelling out the demo account. It's like some people either a.) didn't read the training materials or b.) just didn't care. I don't think it's Sprint's fault at all - the 6 or 7 people I all talked to were dumbfounded how I got a phone that wasn't out yet. I said, "Well, there's another 5,000+ people that would be able to answer that for you". Haha.