Category talk:Hidden categories
Hiding or not hiding categories
The category page have since it was created had a phrase:
|Categories should be hidden if they are concerned with the maintenance or administration of the wiki itself, rather than being part of the content of the encyclopedia.
I am not so sure about the utility of that policy as users will only be able access other pages that need maintenance from maintenance category pages, thus having less people find other pages needing maintenance, as users can not traverse a hidden category from a page unless they look at the source.
I guess this can be overcome by pointing them to the maintenance categories from for example a help page about wiki maintenance or the maintenance messageboxes.