For our customers we usually set the system locale to "de_CG", and make it therefore the default for new users. The reason why the previous commit happened was due to the fact that we forgot this on our development server....
As for confusions with your users at WU, you could put a sentence on the "change locale" page, stating that the WU has austrianized the north german translations and this is the recommended version for students to use. This is perfectly normal, taking into account that you can have some Linux programs running in "Plattdeutsch" as well.
