When a support agent is making a comment/reply to a topic, the default visibility is public. You have to remember to change it before you post, or else the author will be notified. In some support situations, there are far more internal/private comments than public. It could create problems if a support agent thought that s/he were making a private comment, but forgot to change the visibility to "support agents". It would be much safer to default to "support agents" and then have the option to change it to public.
Is there a forum setting (or support agent preference) that will default all comments/replies to private (i.e. "Support Agents")?