People keep calling The Hunt "FATEs without markers," but that's only because that's how we're treating them, and what we expect from open-world content.
Contrary to this, I believe B-rank marks are not INTENDED to be shared with the entire server.
There's an expectation here that, just like FATEs, we should all have a chance every time these monsters pop. I don't think that's a fair assessment of the system, and really, the only problem I see is that Naul and other B-ranks simply don't spawn often enough. Early reports are every hour; how about every fifteen minutes? People will stop carrying this "I deserve a kill" mentality when they happen to miss out on an appearance, and patrolling the zone--actually hunting--will be the most rewarding tactic. I certainly never envisioned telling the whole zone in chat when I saw a B-rank monster--that's my kill/luck for encountering it. There just needs to be MORE of them.