Sorry Goat, no, didn't add anything that you didn't put in there yourself
So I too did some research. I thought I had found out that them finding the tracking device in the crew cabin was not the only one.
I was wrong
First off the diver back in Melbourne I thought had placed a tracking device on the boat. In fact, all he was doing was diving to check the bottom of the boat to see if he could tell which boat it was that Trevor and Shane was on. He correctly identified that it was Atlantis due to the newness of everything on the bottom side.
Then I thought about the 'forensic' expert in Melbourne. He didn't place anything on board in searching for anything out of place, he just got the keys from Trevor where he was able to make an imprint to make copies.
The tracking device was in fact placed on board in ....can't remember what city . The imprinted keys didn't work too well, so he had to force the lock open on the crew cabin hatch. That is where the tracking device was planted. This was further confirmed with Trevor noticing he needed some graphite spray when he noticed the crew cabin hatch's lock sticking.
So I guess that means they are in the clear of the tracking device. Yet it doesn't put Grundig in the clean IMHO. He could have known all along where the tracking device was, but then again maybe he didn't . He also now knows Trevor satellite phone number, so we will see if he makes a few more phone calls to him or to the satellite phone company.
So with my suspicion of Betrayal I have a few suspects; Grundig and Julie. There is also the possibility that it might be Joel's father who has the resort for the honeymoon. It wouldn't be the first time CJ has given us a title which totally misled us, now would it