[quote name='crunchewy']I listed mine not mentioning the option of just getting the code in a message, but then offered that as an option and the buyer took that option. Maybe this doesn't protect me, but it seemed to work out in my case. Once my second one sells, though, maybe I'll just mail it to them. Still seems like you aren't 100% protected, though, as they could claim you sent them a piece of wood instead of a Founder Card, and I'm not sure how you'd be able to say that wasn't true. Hmm. Or more simply they could claim that the code was already used.[/QUOTE]
Take a pic of it, before you ship it. If it is unscratched, you have proof you had an unscratched card. If it is not a covered card you at least have a copy of the code if they say they didn't receive it.
That's about all you can do with the DLC.
I've sold 30 or 40 codes and I only had 2 that people claimed didn't work. One was a scammer and I caught him in a lie, so he couldn't win the claim.
The other may not have actually worked since the guy had 100% positive and was in Canada, so I gave him a refund since it was a low value code.
The DC is the best way to go, but I would also snap a pic just so you have something showing you had a code in your possession at some point. (oh, put the printed invoice in the same pic as well)