Pretty much was Dark just said. The whole size of the zone doesn't matter in regards to the rules, just that their in the zone. However, as a double edged sword here, the rules state that this can't be done if something is done to prevent sensing.
I don't necessarily and completely agree with this. I agree that, eventually, a Jinchuuriki would inevitably be sensed. However for them to automatically sense someone upon entering even in such a huge area is completely illogical. I think that it should take up to a certain number of turns, depending on the size of the zone, for one to be sensed.
As to Kay's post, I'd call that a poetic license. Did she create the jutsu in describing? Possibly, description wasn't just for fun; there was a reason behind it. It could be argued that while describing, she raised the jutsu -- since she'd already typed that much, she didn't really feel the need to type the four or so words of "Kayenta activated the jutsu".
In such, it's a question for her. Did she intend to activate the seal with that post? If so, then it's active; if she intended to wait, then it's not active.
1. I think you have to take in consideration certain statements. For instance, Hono noted that this search had actually been going on for days in RP.
"<赤毛> Honō Uzumaki his idenity, until he spoke however, but that was a none issue. He was on a mission to collect information about Warren, the One-Tails Jinchuuriki.
<赤毛> Honō Uzumaki +
<赤毛> Honō Uzumaki |The thought of this non-combat mission bored him for days, though, he knew Riku could hear his thoughts and would punish him so Hono remained diligent. Though, these odd memories are faintly awaking of a man with Topaz eyes and green.. hair? +"
This has obviously been going on for some time (their tracking of Warren). They may have not posted it in the Zone, but you don't know what's happened let's say in PM or in a dwelling, etc. Then that would raise the question, can private RP carry into a public zone? The answer should be yes. Also, it's not as if it was "Hey! I'm over here, they're over there, let's go!" They acknowledged the fact that it had taken time. Also, jinchuuriki can sense jinchuuriki. Two jinchuuriki are present. As for Kayenta's safeguard, is it even legitimate?
I love the person behind Hono; he's a real-life friend of mine and I have his back, but -- and I'm sorry -- this is illegitimate.
Hono's post in zone one was 5 hours exactly from the time of this post.
(5h21m) <赤毛> Honō Uzumaki cleans up a little before going away from the crowds to smoke.
> (5h18m) <赤毛> Honō Uzumaki would exit Sunagakure gates heading far off towards the edge of the lad of wind. {EXIT}
And before that:
(22h32m) <赤毛> Honō Uzumaki ponders what teh heck is going on at the gates?
--
(23h15m) <赤毛> Honō Uzumaki being the guard for the wedding, he made his way around to the back side of the alter to keep track of all the guest and makes sure nothing goes wrong.
(23h6m) <赤毛> Honō Uzumaki thinks about how many beautiful ladies are in this family.
Honō wasn't stalking the Ichibi; he was attending a wedding. I feel that he thinks he can control it so that, after he left the wedding, he stalked the Ichibi for some time -- but that's not how it happens. The wedding is going on simultaneously to what's going on in zone one. For all intents and purposes, Honō just arrived to the sands.
Is Kay's safeguard legitimate? Yes, safeguards have been shown; she
is a master of chakra. She's been around long enough to justify that.
2. As for Chiyo's powers, I don't know how I feel about that. Essentially, yes, she earned them as a player. But as a character, that's a bit questionable. But then, if a player earns the right to use it, can't they use it on another character as long as they note that it was taken from a past character? It would be like having someone start from scratch.
Her previous character's dead and gone. She has an account now, yes, but hasn't trained up that new character's skills. This is an argument we need verified: how does the Rebirths vs RP scale work? Things need to be emoted, trained; and yet we put such emphasis on rebirths.
I personally feel Chiyo's character should have some skill in her traits, but they shouldn't be mastered until she's trained them.