Everything I've read so far is going on the assumption that Juliette was telling the truth, that they don't know much about Smokey other than the fact it dislikes the fence. What if the Others control Smokey? It seemed to show up every time the two of them started to fight. The thing can put a man in a tree and toss Eko around like a rag doll but, it can pass over a fence? It seemed like a show to me. If that's the case this whole thing could just be a con, to get the Losties to trust Juliette enough to take her in. Juliette stops Smokey from killing Katie (as far as Kate is concerned.) Jack trusts her because she was left behind. She will be on the beach next week. I think the Others sent Smokey out, and pulled him back when the job of freeking Kate out was done. I could be wrong but, it's the only reason I can think of that Smokey would not just hop the fence.

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Hope is a very dangerous thing to lose. - Sayid

I do what my Rice Krispies tell me to. - Anonymous