Edward Craig and Michael Hannon agree that the function of knowledge is to enable us to identify informants whose word we can safely take. This requires that knowers display a publicly recognizable mark. Although this might suffice for information transfer, I argue that the position that emerges promotes testimonial injustice, since the mark of a good informant need not be shared by all who are privy to the facts we seek. I suggest a way the problem might be alleviated.