I doubt that would be possible. The CM's are trained to autograph paper, which has a slick feel. A bear would be very rough and hard to hold within the character's gloves. And remember, most character "eyes" are above a protruding nose. The CM usually sees out of the neck or mouth. Therefore, to make it look like the character is looking at the autograph book, means that the CM will have to hold the book where he can't see it. Yes, they sign the books blind!