For Human-Computer Interaction (HCI) practitioners, interacting with people is a fundamental part of our work. When running any kind of user study, it is important to critically consider any ethical or cultural biases that we (or our data or methods) may have. While this is not a new consideration, the introduction of wearable technology has introduced new aspects to user studies which may not have been apparent previously. In this paper, we present a wearable technology-based user study as a case study to highlight cultural and ethical considerations. Cultural considerations centre on both the cultural considerations that should be made towards participants and considerations for their data. Ethical considerations centre on the immediate impact on participants’ privacy and agency and the longer-term impact on their mental and physical safety. Finally, we suggest that in situations where cultural and racial disparities affect participant expectations and technical results, it is essential to proactively explore these factors.