Is there a configuration setting in Listserv that will prevent
subscribers from selecting "reply-all" in their mail client and
responding to everyone on the list?
 
The configuration Reply-to= Sender, Respect does not prevent a
subscriber from selecting the Reply-All button in their mail client.
What this configuration does is place the original sender's address in
the "to" field when a user hits reply. This differs from Reply-to= List,
Respect because this setting would place the list address in the "to"
field when a user selects reply. But, If a user actually selects "Reply
All" in their mail client it will send to both the list & the original
sender.
 

Olubanke O. Awofeso