I have the latest versions of Joomla and CComment. I have tried every configuration possible of Public->Guest->Manager->...Super User. If I set the built-in Captcha to "Guest", I can still post without logging in, and without Captcha.
If I set Captcha to Public, every level has to use Captcha when posting.

If I set all levels, Guest to Super User, to posting permission except for Public, I get the "You are not authorized to post a comment" message when not logged in. So I cannot even post as "Guest". Guest is like something that does not exist.

The only other thing I can think of doing is requiring "Guest" to register. Then, "Guest" is no longer "Guest" but, "Registered".

I read through "Show captcha only for guests?" https://compojoom.com/support/documentation/ccomment/ch05s04 , and it does not work. The hotlink within the article, "This tutorial", goes nowhere and Produces a page with this message: "[size=4]How do you hide something from logged in users[/size] There is currently no text in this page. You can search for this page title in other pages, or search the related logs, but you do not have permission to create this page." I have spent the entire day searching links and forums for a solution and this is my last resort.

At this point it appears that CComment will not work with captcha unless captcha is required for all levels. If this is not true, then how can the problem be corrected?