Research Software Engineers (RSEs) play a critical role in developing, maintaining, and evaluating scientific software. However, conducting user studies with this group remains uniquely challenging due to a lack of RSE awareness, impostor syndrome, spam responses, and no-shows. In this paper, we reflect on our anecdotal experience of recruiting RSEs for a user study. Based on the challenges that we faced in RSE recruitment, we propose guidelines on how to better recruit RSEs for the user study.