When must tag lines be used according to OSHA 1926.1431 during personnel platform operations?

The correct answer emphasizes that tag lines should be used when necessary to control the platform during personnel platform operations. This means that the use of tag lines is not a blanket requirement for every operation, but rather a situational necessity. Tag lines help ensure safety by allowing individuals to manage the movement and position of the platform effectively, particularly in windy conditions or when navigating around obstacles. This is crucial because maintaining control over the platform prevents accidents and ensures the safety of the personnel working on or around it.

Using tag lines is a recommended practice based on specific conditions rather than a universal rule, which is why this option aligns with OSHA's guidance, allowing for flexibility while promoting safety on site. Other options suggest mandatory usage regardless of circumstance or specific conditions unrelated to safety and operational effectiveness, which does not align with the principles outlined in the OSHA standard.