A few years ago a user single-handedly relocated the centre nodes for each of the 19 Brussels municipalities to their town hall, despite many town halls are on the edge of the area.

Here is the changeset for 1210: https://www.openstreetmap.org/changeset/67885953

IMHO, putting the node on the geographical centre of the area or on a main spot near the centre would make a lot of sense.  (Good example is Halle.)  We could discuss it on the Belgian forum to see what people think would be better.