The Federal Rules of Civil Procedure were amended in December 2015 to help mitigate the risk of inadvertent disclosure of privileged information present in virtually every litigation. Such risk, however, is particularly acute in litigation involving trade secrets, non-competition, non-solicitation, and/or non-disclosure agreements.

Employee mobility litigation poses a special risk for inadvertent disclosure because of the email address “autofill” function common in various email programs. Needless to say, employees use work-issued email accounts. Even after the employee leaves the company, the email account often remains active and may be monitored by the former employer, especially if the employee and company become litigation adversaries.

Two true stories highlight the risk:

Former employees, call them Ms. X and Mr. Y, were involved in a trade secret dispute with their former employer, a corporation. Ms. X emailed Mr. Y and their joint-defense counsel regarding the case. Unbeknownst to Ms. X, she accidently sent the communication to Mr. Y’s old work-issued email address, which had been saved by Ms. X’s personal email account and “autofilled” when she typed Mr. Y’s name into the address box in the email. Because the former employer was monitoring Mr. Y’s email address, they became privy to the privileged communication.

Making matters worse, neither Ms. X nor defense counsel caught the mistake, because their email header showed only that “Mr. Y” had been sent the email, without indicating Mr. Y’s actual email address. Ms. X and defense counsel, using “reply all,” exchanged numerous communications in the email chain before the inadvertent disclosure was discovered.

This horror story is all too common in litigation, and no one is immune. For example, this “autofill” trap recently caused Jared Kushner’s attorney to inadvertently disclose sensitive information to an email prankster. The attorney had emailed with the prankster, believing he was corresponding with his client. But thanks to “autofill,” discovering that the prankster was not actually Jared Kushner did not prevent later inadvertent disclosure. Mr. Kushner’s attorney received an email from the Senate Intelligence Committee, which he attempted to forward to Mr. Kushner, but he mistakenly sent the email to the prankster’s fake email account, likely because his email program saved the prankster’s email address and “autofilled” it in when he intended to address his email to his client.

This type of inadvertent disclosure raises difficult questions regarding whether to alert opposing counsel of the disclosure, especially if opposing counsel is less than scrupulous. On the one hand, alerting your adversary is prudent because it imposes an ethical and likely legal duty upon the adversary to sequester or destroy the inadvertent transmission.

On the other hand, if opposing counsel is unscrupulous, notifying them of the inadvertent disclosure only highlights the disclosure (which otherwise might never have been noticed) and makes it more likely that the privileged emails will be reviewed.

The important takeaway is to always be sure to identify the work email accounts of clients who are adverse to their former employers, and take care that those email accounts do not “autofill” in your email program. Educate your clients about this issue early on so that they, too, can take steps to ensure they don’t inadvertently send emails to their former employer.

If you learn that such an inadvertent disclosure occurred, consider the risk and benefit of alerting opposing counsel and instructing them not to review the email. Unless you are dealing with unethical counsel or an unethical former employer, this generally will be prudent.