Because sometimes it is. This is widely understood in health epidemiology. There are no screenings or interventions with zero risk: https://www.bmj.com/content/

Because sometimes it is. This is widely understood in health epidemiology. There are no screenings or interventions with zero risk: https://www.bmj.com/content/352/bmj.h6080 https://www.bmj.com/content/352/bmj.h6080