Here is a little picture story from one of my moderators. The story contains two different problems. One is the new post indicator and one is that he can see hidden boards. Let's begin:
This is the view to the first board in a category. This board contains only subdirectories and no postings. The writing access is limited to Admins to post urgend messages here.
As you see the green LED indicate new postings and the last post show on the right. The Moderator hase NO access to 'World of Warcraft - Core' but it show up in the sub board listing of the red marked board. The core is the third sub level, horde pvp is second sublevel and we are now in the first level.
Now we enter 'World of Warcraft - Horde PvP to look to the new posting.
You see that only 2 more sub boards exits, the core board don't show up, that correct because the user have no access to this board. But you see also that the green LED is off now. Lets enter the red highlighted board:
Here you can see that this posting not triggered the LED on the top level. So my Idea is, that a posting in a board, that the user cant see because he have no access trigger the indicator of new postings and thats wrong.
Can you follow?