Is the subject line of a classified email considered a banner line?

The subject line of a classified email is not considered a banner line. A banner line typically refers to the classification markings that appear at the top of the document or message itself, indicating the level of classification and the handling instructions. These markings serve to alert the recipient about the sensitivity and required protections for the content of the communication.

While the subject line can provide important context about the content of the classified email, it does not serve the same purpose as a banner line, which is specifically aimed at conveying classification status and ensuring that recipients are aware of the need for safeguarding the information. Thus, the classification markings and banner line must be clearly indicated as part of the document formatting, separate from the subject line.