Researchers increasingly use online tools to advertise studies, recruit participants, and collect data, enabling access to individuals in remote or rural areas, those with limited mobility, and participants facing time constraints. While online platforms offer significant advantages, online research remains vulnerable to fraudulent activity, which can compromise the validity of study findings and deplete both funding and human resources. This special communication describes the real-world experiences of two research groups, one in Canada and one in the United States, who encountered fraudsters in both randomized controlled trials (RCTs) and observational studies.