Let's suppose this gets implemented. What happens if a Newbie's posts are rejected? Does he get an instant ban, or can he keep posting more and give Mods a large work load? If he gets banned he'll probably just create another account. What about the thousands of bots that are spamming the forum now?
No, but it would depend on the type of post. Obviously bot accounts would be nuked on sight and I guess whether a genuine user is warned or banned or not would also depend on the post but that would be up for debate/discussion before this system was ever implemented. I don't think I would ban people straight away and have always rather warned people that gone straight to a ban, but I would rather the thread be trashed and they told the reasons why via PM (unsubstantial or duplicate thread or whatever).
I can imagine it works well once the forum is healthy, most new users create legitimate posts and a few users per day need banning. On Bitcointalk, we currently have 34000 posts, most of it spam, which would instantly lead to a very large backlog and large delays for the few new real users this forum has.
But we wouldn't be verifying all the 34000 posts. When I initially proposed it it was more of a solution to stopping bots and only a user's first post or so would need to be verified by a staff member. To them the post would still show up as normal but not to everyone else until it has been approved. If it hasn't been accepted or declined by a mod I think it would be helpful to state the reason so people can learn from their mistakes or what is an isn't acceptable here and at least spam threads from newbies will almost be eliminated.