I currently have 17 forums in total on my site, with one hidden from all the other users. The forum stats box tells the normal users that there are 17 forums though, so they know there's a hidden one. Shouldn't the stats box only tell them there's 16 forums?

I think it should keep it hidden as well unless they have rights to enter that forum.

The problem is that the stats are cached, and depending on your group setup and permission layout the number of forums that people can actually view will vary greatly. The only way to get an accurate count would be to have it a live query, but it's a fairly complex one and to display on every page wouldn't necessarily be a good thing.

I picked up on this, but after a while its not that important,
most forums have at the least one hidden, for admin and moderators as i picked that up on these forums too.

We have an admin forum? wheres that hidden at lol