The experimental studies presented here investigated whether discussing ethical implications of preliminary scientific results in a science blog would impact blog readers’ perception of the responsible scientist blogger’s epistemic trustworthiness (on the dimensions expertise, integrity, and benevolence). They also investigated whether it made a difference in who had brought forward the ethics aspects: the responsible scientist blogger or another expert. Results indicate that by the mere introduction of ethics, people infer something about the blogger’s communicative intentions: Introducing ethical aspects seems to raise vigilance about an expert’s benevolence and integrity. Moreover, ratings of epistemic trustworthiness differed depending on who added ethical arguments: If ethics were introduced by the scientist blogger himself, his benevolence and integrity were rated higher than when ethics were introduced by another expert. These results are relevant for science bloggers, science communicators, and researchers who study laypeople’s understanding of epistemic uncertainty within science.