When a speaker makes an assertion, she commits herself to the truth of some proposition. She thereby knowingly takes the risk that her addressee examines the reliability of her assertion by either checking the content of the asserted proposition or by scrutinizing her epistemic and moral authority. The addressee’s choice is to either fulfill the speaker’s communicative intention or not. She can further do it on the sole ground of the speaker’s authority or not. As I see it, the issue of whether the addressee could wrong the speaker by committing some epistemic injustice towards her cannot arise in the process whereby the addressee assesses the reliability of the speaker’s mere assertion of P. It can only arise if and when the speaker offers some explicit argument in favor of proposition P, in the reasoning process whereby the addressee evaluates the speaker’s explicit argument in favor of P, i.e., the link between P and the premises selected by the speaker to justify P. Only then could the addressee produce an ad hominem counter-argument (either local or global) meant to successfully or unsuccessfully rebut the speaker’s argument for P.