I keep thinking that it HAD to be set up like that. There is no way that someone could be that stupid, but unfortunately, I think Erik was THAT naive. I don't understand his thinking, he even told Natalie, "why would it matter if I gave you the necklace or not -- to Cirie, if she is voting for Amanda?"
I kept waiting for him to ask Nat/Cirie what their backup plan was in case he didn't give up the necklace, but he didn't even try to catch them in that.

It was obvious from that editing that he was going to do it; once the idea was mentioned, there was nothing else shown at all...I do have to wonder how the votes would have gone if he had decided to keep it (say, from seeing the jury looking at him like "Are you a F%cking MORON??").