I think if it was some random book he wouldn't - but if someone was able to lug "Knowing Darkness" to a signing, I can't imagine him refusing to sign it. But again, it's the perfect storm of factors - you have to get the book TO the signing, it has to be a signing where you can bring a book, and so on. AND it has to be the book someone WANTS signed. So it's a theory that may never have an answer!
But I agree with Carlos above - I don't know why Jerad is SK's whipping boy. He's put out better quality, inspired limited editions than many publishers and should have earned more respect. But once a guy like King gets a thought in his head it's going to be hard to change his mind.