Have you ever tried to closely listen to two people talking simultaneously? It's very difficult. It's very easy to get confused.
Yes, there was something under his jacket. It may have been all sorts of things. I cannot believe, though, that it was something that would allow GWB to get tips or pointers from handlers. Radio receivers can be *tiny* these days. Why would they need something that big if Bush was going to be listening to directions? If it needed to be that big, why wasn't it hidden in his pants rather than on his back?
My vote is that it had something to do with a bulletproof vest or something else that would need to be around his chest.
My $0.02.
Cheers,
Scott.