Each individual Karbon user is able to adjust their Auto-share email setting themselves. While no one is able to adjust this setting for others, you can see who has chosen to turn this setting on and who hasn’t.
To see this, navigate to Settings > Colleagues. This will list out everyone on your team and include a column listing the auto share email settings of each user.
Clicking this will take you to a complete list of all colleagues who are sharing their email communication with the contact's email address. Below, you can see any colleagues who are not sharing their email communication.