A more thorough explanation:

The middle-of-the-road test is a principle used to determine whether an inadvertent disclosure of a privileged document waives the attorney-client privilege. The court considers several factors, including the precautions taken to prevent the disclosure, the number and extent of disclosures, the promptness of any efforts to remedy the disclosure, and whether justice would be best served by allowing the disclosing party to retrieve the document.

For example, if a lawyer accidentally sends an email containing privileged information to the wrong recipient, the middle-of-the-road test would be used to determine whether the attorney-client privilege has been waived. The court would consider whether the lawyer took reasonable precautions to prevent the disclosure, such as using encryption or double-checking the recipient's email address. The court would also consider the number and extent of any other disclosures, as well as the promptness of any efforts to remedy the disclosure, such as requesting that the recipient delete the email. Finally, the court would consider whether justice would be best served by allowing the lawyer to retrieve the email.

Another example might involve a company accidentally producing privileged documents during discovery in a lawsuit. The middle-of-the-road test would be used to determine whether the company waived the attorney-client privilege by producing the documents. The court would consider the precautions taken to prevent the disclosure, such as conducting a thorough review of the documents before producing them. The court would also consider the number and extent of any other disclosures, as well as the promptness of any efforts to remedy the disclosure, such as requesting that the documents be returned. Finally, the court would consider whether justice would be best served by allowing the company to retrieve the documents.