When my 3ds broke and I bought a new one I just emailed nintendo telling them what happened and asked for my NNID to be unlinked from the broken 3ds. They repied with a few quick questions and once I answered them they unlinked the NNID. All done in under a hour.
I would imagine it would work exactly the same for the WiiU so just send them an email
While I know you mean in case of someone confusing schooling establishment from shooting establishment (many of the same letters) I am still going to read that as lockdown (also known as lock in) for a pub
being drunk in school was either because drunk on playing field or could not be arsed with one particular Thursday afternoon so went and had some beers and played some games instead before returning for an ill advised last lesson/period