That night, Jaime goes through James's bag, hoping to find something. Interestingly, as we've discussed in the past, reactions to going through people's stuff tend to be highly specific to the circumstances and the person; surprisingly, there's not always much huffiness about the sacredness of anyone's belongings unless it's someone you like. The advent of the hidden idols seems to have caused a lot of these folks to see each other's possessions as somewhat less sacrosanct than before. But right or wrong (more of the latter), in the darkness, Jamie goes through the bag enough to ascertain that James has two of the squares like the one she and Erik have, which are wrapped in his clothes. She knows that James was just kidnapped, so she knows he has fairly well-developed information about the hidden idols, so if he has these wrapped up, she's pretty confident that idols are what they are. "He has two of them," she emphasizes to Erik. So she knows that James has taken down three things that she knows are similar, and that he's hidden two of them and left one out. Perplexing.
The next day, James looks around camp as he voices over that he had pulled down the first plaque and not bothered to conceal it anywhere, so he was surprised to find that it was no longer where he left it. He puts together that this could mean that someone in camp has it and believes it to be an idol. James stresses in his interview that it would be incredibly stupid -- stupid Jaime, dumb as a festival of paper clips! -- to think that an idol wouldn't say immunity on it. He's right, except in the sense that he may have missed the previous seasons of the show in which the immunity idol never said "immunity" on it, but instead came with notes or instructions with it -- which, presumably, someone would assume were gone if they believed you found the idol, and which certainly wouldn't be a good reason on its own to reject something that fit all the other clues. The irony of this is that the show constantly does that spooky-threat thing where Jeff cautions people not to assume anything, like it's a constantly evolving Rube Goldberg device with a twist around every corner, when, in fact, you can usually assume lots and lots of things. What's killing Jaime here is that she's not assuming anything. She's not assuming that there couldn't be three idols, she's not assuming that the idol would have to have "idol" printed on it in English, and she's not assuming that the fact that it wasn't concealed means it couldn't possibly be the idol. That last one she kind of has to handle that way, since otherwise, you could hide any idol simply by leaving it out in plain sight, so you can't assume that just because you find it, it can't be an idol.
James -- quite understandably, given the fact that the other members of Zhan Hu were trying at one point to throw challenges to eliminate him -- says it would thrill him to no end if Jaime has a fake one and thinks it's a real one. He giggles at the very thought of her trying unsuccessfully to play it at tribal council. I certainly don't blame him for relishing the thought of her losing out, with the caveat that you always have to beware that you don't put too much of a karmic whammy on yourself while trying to deliver one to someone else. James is the very picture of a very, very happy giant gravedigger.