Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

It really is a brilliant point that if you accept that the two horn honks were signals, then surely they could not have been signals to Jack Ruby. It is insane to think that the Dallas Police would have installed Jack Ruby to actually be the one wielding the gun and shooting Oswald. Furthermore, if that were true, then everything that happened afterwards between the Dallas Police and Jack Ruby was a big act. In other words, it would mean that they were in on it together, that they were accomplices. And why on Earth would Jack Ruby do such a thing? It's ridiculous. So, if those horn honks were signals to the shooter, the shooter had to be somebody else. He could not have been Jack Ruby. He was, in fact, James Bookhout.