Formal Opinion 503 addresses ABA Model Rule 4.2, the no-contact rule, which says that a lawyer representing a client may not communicate about the matter with another represented person, unless that person’s lawyer consents.
The new ABA Opinion summarizes its conclusions:
“Reply All” in Electronic Communications In the absence of special circumstances, lawyers who copy their clients on an electronic communication sent to counsel representing another person in the matter impliedly consent to receiving counsel’s “reply all” to the communication. Thus, unless that result is intended, lawyers should not copy their clients on electronic communications to such counsel; instead, lawyers should separately forward these communications to their clients. Alternatively, lawyers may communicate in advance to receiving counsel that they do not consent to receiving counsel replying all, which would override the presumption of implied consent.