Personal health technologies are increasingly introduced in workplace settings. Yet little is known about workplace implementations of activity tracker use and the kind of experiences and concerns employees might have when engaging with these technologies in practice. We report on an observational study of a Danish workplace participating in a step counting campaign. We find that concerns of employees who choose to participate and those who choose not to differ. Moreover, privacy concerns of participants develop and change over time. Our findings challenge the assumption that consumers are becoming more comfortable with perceived risks associated with wearable technologies, instead showing how users can be initially influenced by the strong positive rhetoric surrounding these devices, only to be surprised by the necessity to renegotiate boundaries of disclosure in practice.