I've just also noted that posting to a BS thread, you automatically get 'jumped' back to the top of the main list, not the BS. As the message only jumps part way up some may think their post hasn't made it, and while they would spot that on re-entering the thread, and so not re-post, it is possible that someone might duplicate a Newly created BS thread when they don't spot it at the top of the list.
Nigel