When I merge tickets, the confirmation pop-up defaults the merge comment to public. I have to uncheck the Requester can see this comment boxes every time I merge tickets if I don't want the requester to get those emails.
How can I make merged tickets' comments private by default?
Go to Admin > Settings > Tickets > Comments > and uncheck Agent comments via web are public by default. When this option is selected all comments made by agents will be set to internal notes by default unless that agent manually changes the comment to a Public reply.