If you bought a pre-owned Wii U (yes, some Impatient Irvings are already selling theirs back) you may want to browse through the eShop real fast. If the previous owner picked up any games on the console, chances are they'll be ready to re-download free of charge.
Multiple NeoGAF users noticed surprise downloadable windfalls on their systems. Despite the customary data wipe for most resellers, the purchase information is still tethered to the console through Nintendo Network; Suddenly pre-owned consoles could be of significantly greater value than their new counterparts--depending on how download-happy their previous owners were.
It makes sense, given that Nintendo Network IDs are tethered to the system they're created on, and any user can enjoy a given console's eShop purchases (we'd hate to be the Indecisive Irene who buys another Wii U after selling their first one). Still, we hardly imagine this was an intentional incentive from Nintendo, who say they are looking into the matter.
We'll update this story with any further comment from Nintendo.