Customer mistreatment is a pervasive workplace stressor with well-documented negative effects on employee well-being. Emerging research suggests that third-party observers, employees who witness but are not directly involved in such incidents, can also experience emotional and behavioural consequences, such as empathy toward the mistreated coworker and subsequent helping behaviour. However, this literature often overlooks a key practical reality: observers are not the only third party. To mitigate the impact of customer mistreatment, many organizations now mandate managerial intervention. Yet little is known about how such interventions shape observers' interpretations and responses.
Drawing on deontic justice theory and Affective Events Theory (AET), this research examines how two forms of managerial intervention, instrumental support (e.g., addressing the customer conflict) and emotional support (e.g., affirming the employee's experience), influence observers' empathic responses. We argue that these supports serve distinct yet complementary signalling functions: instrumental support highlights the severity of the mistreatment, while emotional support validates the employee's suffering. Together, they enhance empathetic responses among third-party employees, which in turn promote innovative service behaviour: proactive efforts to improve service delivery and prevent future mistreatment. We found empirical support of our hypotheses across an experimental vignette study (Study 1) and a multi-wave field study (Study 2). This research advances the literature on workplace mistreatment by positioning managerial intervention as a key driver of third-party outcomes. It also identifies empathy as a mechanism linking intervention to constructive behaviour aimed at improving service quality, offering practical insights for organizations seeking to foster resilience and service improvement in customer-facing roles.