Regretably as late as the 1980s someone still managed to fit a helicopter individual tail rotor blade the wrong way round, so the trailing edge was wrongly facing the rotational airflow. The remaining blades were fortunately the right way round. The pilots were alert to the extra vibration during ground taxi before getting airborne and it didn't lead to disaster (I think). All it needed at design phase was different retaining bolt diameters; rather than the ineffective outboard/inboard label. Murphy's Law.