A wearable computing device includes: a wearable housing; a display assembly supported by the housing and switchable between (i) an active configuration to occlude an optical path between an operator field of view and an exterior of the wearable computing device, and (ii) a fail-safe configuration to clear the optical path; and a mitigation subsystem including an actuator controllable to switch the display assembly from the active configuration to the fail-safe configuration in response to detection of a display failure condition.