Product counterfeiting is a large and global economic crime that causes significant economic, social and personal harms. Facilitated by the efficiency and convenience of e-commerce, finding and buying counterfeits have never been easier. Going beyond product listings on websites, counterfeiters are now using sophisticated marketing techniques to promote their illicit wares. This includes employing deviant social media influencers who violate social norms and the law to peddle counterfeit goods via channels such as YouTube and Instagram. However, very little is known about their market or their impact. Based on two UK surveys, the empirical research described in this article estimates the prevalence of consumers who purchase counterfeits because of SMI endorsements. We believe this is the first estimate of its kind anywhere. Further, the research finds that influencer marketing exploits characteristics of consumers that make them susceptible to the charms of the deviant SMIs: high susceptibility to the influence of trusted digital others, low risk awareness, high risk appetite, and prone to rationalizations that morally justify the purchases. The higher prevalence of these characteristics in young adults and males helps to explain why these demographic groups are the most likely to purchase endorsed counterfeits.