That's a really good question.
For search and rescue purposes, which was the main driver behind this.... This was obviously to identify a vessel through its transponders for search and rescue purposes. So there was no reason to transfer them.
If you're talking about a security point of view, it's possible. It is possible. Whether it can happen or not, I can't comment. There are multiple layers built into the system to prevent that from happening, but it is conceivable, in this day and age, that somebody could possibly do it.