Hey Tom,
Course visibility based on audiences is not possible at the moment, it is however a much requested feature so we are looking into it.
As for the facetoface calendar, there are multiple settings (Totara 2.2.11+) under Calendar Options. One is "Calendar Display Options", where you can choose which calendar the sessions display on (site, course, none) it sounds like at the moment you have it set to site, which will allow everyone using your site to see it on their calendar. Try changing that to course or none, course will allow only the people enrolled in the course to see it, none will allow no one. Under that is "Show entry on user's calendar" which adds a calendar item to a users personal calendar when they sign up for a session, I advise at least leaving this on so people have a reference on their calendar. Only the users signed up for a session will see these.
Hope this helps,
David
Course visibility based on audiences is not possible at the moment, it is however a much requested feature so we are looking into it.
As for the facetoface calendar, there are multiple settings (Totara 2.2.11+) under Calendar Options. One is "Calendar Display Options", where you can choose which calendar the sessions display on (site, course, none) it sounds like at the moment you have it set to site, which will allow everyone using your site to see it on their calendar. Try changing that to course or none, course will allow only the people enrolled in the course to see it, none will allow no one. Under that is "Show entry on user's calendar" which adds a calendar item to a users personal calendar when they sign up for a session, I advise at least leaving this on so people have a reference on their calendar. Only the users signed up for a session will see these.
Hope this helps,
David