Which statement is true regarding the use of a separate shipper's declaration?

The correct answer highlights the necessity of a separate shipper's declaration for shipments managed by freight forwarders. This statement is significant because freight forwarders are responsible for the logistics and documentation required for transporting goods. When working with freight forwarders, a shipper's declaration provides critical information about the nature of the cargo, any special handling requirements, and compliance with regulations.

This declaration is crucial for detailing the type of goods being shipped, particularly for air cargo, where security and safety regulations are stringent. It helps ensure that all parties involved in the shipping process are aware of any hazards or regulations that must be followed. Additionally, having a thorough declaration assists in clearing customs and protecting against legal liability in case of issues during transport.

In contrast, while some aspects of other options allude to situations in which a shipper's declaration might not be necessary, they do not accurately reflect the consistent importance of a declaration with freight forwarders or in air transport overall. The need for documentation can vary depending on specific circumstances, but it remains foundational for maintaining compliance and safety in the shipping industry.