I'm not sure how this would work. Zombie Sat is "bent pipe" meaning that it takes what it receives and amplifies it and retransmits it back down to Earth. So in order for there to be anything on it, assuming it's not intercepting signals meant for another satellite (more on that later), then the up-linker would have to have their ground up-link satellite constantly moving to keep up with its zombie actions.
Now if its interfering with another satellite and retransmitting its signal, then for all intents and purposes it is that satellite it's stealing from. But since different satellites have different polarities and what not, it would probably just make interference.
So to directly answer your question, the interesting stuff from Zombie Sat is the news stories wrote about it and the engineering challenges they are trying to overcome.
