Everyone is open to having the line status on their phone monitored, by default. If a user wants to prevent a specific person from monitoring their line status, you, as an administrator, can configure the user's privacy settings and determine how they can be reached by an Auto Attendant. For example, an executive may want their administrative assistant to see when they're on the phone but not another executive.
From the customer view in https://admin.webex.com, go to Users, and select the user you want to modify.
Select Calling, go to Between-User Permissions, and enable Privacy.
Choose the appropriate Auto Attendant Privacy settings for this user.
Check the Enable Privacy check box. You can then decide whether to block everyone by leaving the Search user by name field empty or choose who can monitor this user's line status.
Using the executive example above, you'd search for the name of their administrative assistant.