Or to trade the download key to for a physical disc. Which was ridiculously tedious if you're not prepared.

Expectation? Have the download key, your gamertag, email address and mailing address. Easy.
Well, you need your console registered to your account, or have your serial # (I did not have either as I was at work hoping to get it ordered asap). Additionally, I needed to provide proof of purchase, photos of my box, my receipt, and the front and back of the download card, even having provided the valid code... I was first asked in chat to send the photo, of course you can't in chat so I had to ask how; the rep then had to send me an email I could reply to with the attachments, to which of course I got a reply saying the support system couldn't handle my attachment because it was either too big, or wasn't one of the enormous list of pretty much universally accepted and safe file types (it was a 400k jpg - perfectly valid); but it seems the emails did go through and they did get the photos...

suffice to say it wasn't a smooth process, and certainly not as simple as the trade-in instruction page suggested it would be. If you're lucky enough to get that quick 'n easy, in-and-out process, you are very fortunate.

Digital download trade? I've never said so sincerely - Were it so easy...