(a) In representing a client, a lawyer shall not use means that have no substantial purpose other than to embarrass, 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 relating to the representation of the lawyer's client and knows or reasonably should know that the document was inadvertently sent shall promptly notify the sender.
 Responsibility to a client requires a lawyer to subordinate the interests of others to those of the client, but that responsibility does not imply that a lawyer may disregard the rights of third persons. It is impractical to catalogue all such rights, but they include legal restrictions on methods of obtaining evidence from third persons and unwarranted intrusions into privileged relationships, such as the client-lawyer relationship.
 Paragraph (b) recognizes that lawyers sometimes receive documents that were mistakenly sent or produced by opposing parties or their lawyers. If a lawyer knows or reasonably should know that such a document was sent inadvertently, then this Rule requires the lawyer to promptly notify the sender in order to permit that person to take protective measures. Whether the lawyer is required to take additional steps, such as returning the original document, is a matter of law beyond the scope of these Rules, as is the question of whether the privileged status of a document has been waived. Similarly, this Rule does not address the legal duties of a lawyer who receives adocument that the lawyer knows or reasonably should know may have been wrongfully obtained by the sending person. For purposes of this Rule, "document" includes e-mail or other electronic modes of transmission subject to being read or put into readable form.
 Some lawyers may choose to return a document unread, for example, when the lawyer learns before receiving the document that it was inadvertently sent to the wrong address. Where a lawyer is not required by applicable law to do so, the decision to voluntarily return such a document is a matter of professional judgment ordinarily reserved to the lawyer. See Rules 1.2 and 1.4.