(a) In representing a client, a lawyer shallnot use means that have no substantial purpose other than to embarrass, delayor burden a third person, or use methods of obtaining evidence that violate thelegal rights of such a person.
(b) A lawyer who receives a document orelectronically stored information relating to the representation of the lawyer?sclient and knows or reasonably should know that the document or electronicallystored information was inadvertently sent shall promptly notify the sender.
 Responsibility to a client requires alawyer to subordinate the interests of others to those of the client, but thatresponsibility does not imply that a lawyer may disregard the rights of thirdpersons. It is impractical to catalogue all suchrights, but they include legal restrictions on methods of obtaining evidencefrom third persons and unwarranted intrusions into privileged relationships,such as the client-lawyer relationship.
 Paragraph (b) recognizes that lawyerssometimes receive a document or electronically stored information that was mistakenlysent or produced by opposing parties or their lawyers. A document orelectronically stored information is inadvertently sent when it is accidentlytransmitted, such as when an email or letter is misaddressed or a document orelectronically stored information is accidentally included with informationthat was intentionally transmitted. If a lawyer knows or reasonably should knowthat such a document or electronically stored information was sentinadvertently, then this Rule requires the lawyer to promptly notify the senderin order to permit that person to take protective measures. Whether the lawyeris required to take additional steps, such as returning or deleting thedocument or electronically stored information, is a matter of law beyond thescope of these Rules, as is the question of whether the privileged status of adocument or electronically stored information has been waived. Similarly, thisRule does not address the legal duties of a lawyer who receives a document orelectronically stored information that the lawyer knows or reasonably shouldknow may have been inappropriately obtained by the sending person. For purposesof this Rule, "document or electronically stored information "includes in addition to paper documents, e-mail and other forms of electronicallystored information, including embedded data (commonly referred to as?metadata?), that is subject to being read or put into readable form. Metadatain electronic documents creates an obligation under this Rule only if thereceiving lawyer knows or reasonably should know that the metadata wasinadvertently sent to the receiving lawyer.
 Some lawyers may choose to return adocument or delete electronically stored information unread, for example, whenthe lawyer learns before receiving it that it was inadvertently sent. Where alawyer is not required by applicable law to do so, the decision to voluntarilyreturn such a document or delete electronically stored information is a matterof professional judgment ordinarily reserved to the lawyer. See Rules 1.2 and1.4.