American Bar Association - Rule 4.4: Respect for Rights of Third Persons lyrics

(a) In representing a client, a lawyer shall not use means that have no substantial purpose other than to embarra**, delay, or burden a third person, or use methods of obtaining evidence that violate the legal rights of such a person. (b) A lawyer who receives a document or electronically stored information relating to the representation of the lawyer's client and knows or reasonably should know that the document or electronically stored information was inadvertently sent shall promptly notify the sender.