When Cody faces off against Tank for the first time, Cody takes a wipe-out. We then see a few instant replays. On the second and third replay, we see Tank leaving the tube. One the fourth, however, he doesn't leave the tube.
After the argument with Big Z, Cody rips his big Z necklace off and during his walk to the line up its clearly seen that he's no longer wearing it, However in the long shot of the line up, you can see that Cody has the necklace on..and then in the following closeup its gone again.