I had the same issue on my D2G. They took one look at it at the VZW store, verified my warranty status & started processing. No questions, or hassle.
Now I have a certified pre-owned D2G enroute. I am apprehensive though. My D2G has never been rooted and runs like a dream. I know it could be better, but it rarely screws up at all. You read all of these stories online about CPO phones coming DOA or only lasting a few weeeks before they crap out. I hope I didn't trade one problem for another.
I just keep telling myself that no one gets a CPO phone that works great & posts on the internet how happy they are. It's only the problem ones that make the boards.