Shouldn't these possible hunters look towards the series and how it was done? It can be done as subtly or aggressively as desired. They could go in there, metaphorical guns a'blazing and fight all they can to get to where their prey is (like how I believe Hidan and Kakuzu did with Yugito). Or, they could sneakily make their way through, not doing anything that could really give away any sort of IC (physical) intention of hunting anything. Basically they could simply do what Yujo did in terms of his moida of Ichirou... and Uetto... basically everybody that sneezes in his general direction.
Of course, they'd have to IC know of the status of the Jink, i.e whether or not he's a well known Jinchuriki in the first place... Much like Athos is/was with the Six-Tails. I'm sure there's people who IC still believe the man is the host of the slug. That would, in my opinion, make it so that people would actually have to RP and move around the various countries in the realm if they want to have a chance of gaining any sort of Biju as their own. Like say someone like... uhhh some random and new smurf/smurfette gets a Biju. He/she trains with it, masters it and continues to do their thing. They keep up their RP duties and doesn't really let it be known that they have said beast. How would these hunters know this person is the container, because there's nothing really going on in the realm that would let anybody really know people from other countries? Sure there's connections, but it's really the OGs that know each other. Sure this Serean thing is still going on, but with the Suna seals being passed around, people are most likely going to be going back to staying in their villages and being lax and goody goody all day.
I forgot the gist of what I really wanted to say, but give me a moment while I think....
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Oh wait, yeah for those organization leaders, (ROOT, Manji, Akatsuki, the reverse Akatsuki (forgot what it was called) and whatever the other villages have) gathering the intelligence with their resources could be a good way to RP some NPC espionage as well. I'm not sure if anybody else is down for this, but Manji personally is set for this sort of thing. I'm saying, someone could RP a way to get in touch with one of these organizations, if they don't have a way of gathering their own intel, and could go further in their hunting process. I'm just spitballing ideas to get people to RP more and meet newer people every so often. If the desire for a one-on-one is what the challenger wants, then they can bring it to the forum or zone. Sure, this could lead to the RP on the board to become staggered, but at least it'd still be IC.
Oh wait, if someone has more than one Biju and loses, shouldn't the others under their control be released as well? That's the thing with IC, most people don't want to face the chance of losing their character. I understand it, but it leads to voids being enforced. Obviously, I went off track, so I'm going to just end this here and go back to whatever I was doing >.>