Deleted your account? Terrific. Wiped your hard drive? Good for you. Guess what? Your downloads might still be playable by the next owner of your machine.
It might seem like some kind of urban legend, but it looks like it’s true. Purchase history from the eShop is apparently tied to the actual physical console itself and not your user account.
So even if you take all the necessary steps to wipe your record clean from your console before you trade it into a reseller (or give it to a pal), whoever owns it next can grab all your content gratis.
Only Nintendo can transfer downloaded items and accounts from console to console at this point, a fact that leaves users very little power over their digital Nintendo lives. So with that in mind, the long and the short of it is that if you trade away your Wii U- you also trade away all of your digital content with it.
It remains to be seen what, if anything, will be done about the unintentional freebies down the line. As of now though, it looks like free games may be in the cards for you if you buy in for a used Wii U.