They actually asked me to. And the box wasn't empty per-say, it was just missing the graphics card. It had the power adapters/manuals and such still, as well as the original NVIDIA box. It was a used item, so it was expected to be opened.
Sure, but the main item was missing. Like other posters have said - you paid Amazon to deliver an item, that item was missing. There was nothing to return at all in my opinion and I would have refused any request to return from amazon. I know hindsight and all, but yeah. If your account is in good standing Amazon would(should?) just refund it. If you have a new account or if you did this a few times already they will be pissy about it.