What is the primary purpose of a warning order?

The primary purpose of a warning order is to alert the patrol members so that they can begin preparations for an upcoming operation. This order serves as an initial communication that provides essential information regarding impending actions, allowing team members to start organizing their equipment, planning their courses of action, and fulfilling any administrative requirements necessary for mission readiness. By receiving a warning order, personnel can effectively prepare themselves for the mission's requirements, ensuring they are ready to execute tasks efficiently once the operation begins.

In this context, the other options do not align with the fundamental goals of a warning order. A debriefing pertains to reviewing and analyzing an operation after it has occurred, which is separate from the preparatory actions indicated by a warning order. Informing the enemy contradicts the purpose of maintaining operational security and tactical advantage, as a warning order is meant for internal communication only. Establishing communication lines, while important in planning, is not the primary focus of a warning order; rather, it comes into play during the execution phase of an operation.