Rumor: Used Wii U consoles allow one to download previous owners digital games - Pure Nintendo
A Neogaf member claims that purchasing a used Wii U consoles will allow that new owner to download the previous owners digital games. According to reports, eShop cames are not specific to Nintendo ID but to the system as a whole. This means every account has access to a downloaded digital game.
This could be a big problem if this comes across as true.