Well, if I'm reading this right we're gonna find out if your idea will work or not.
http://www.ign.com/articles/2014/02/27/nintendo-terminating-wi-fi-service-for-ds -and-wii
Here's the effected game list that for some reason takes a few clicks to get to the full list.
http://www.nintendo.com/consumer/gameslist/games-wifi.jsp
The link above takes you to page 2. There are multiple pages, but that page lists the COD games.