Can we make the "Off Topic" board only visible to logged in members only ?  We also have the ability to block posts from unwanted members. Can the same idea be implemented for unwanted topics/boards ??

I recommended that  a few years ago. It was tossed out by the admin because the off topic section may be of general interest also to non members... 

@Alex: I agree totally with you. It's very annoying with this mess of off topic themes. Thought that was a lighting-gallery..
However potentially new serious lighting enthuasiasts will that scare off to join this website.