(a) In representing a client, a practitioner 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 practitioner who receives a document or electronically stored information relating to the representation of the practitioner's client and knows or reasonably should know that the document or electronically stored information was inadvertently sent shall promptly notify the sender.