Hi Chad
I completely understand what you are trying to accomplish. We have that same request of teachers and we also have TAs/Student coaches/parents who we do not want listed in the participants list because they are not actually participants (more like observers).
I tried what you stated here and had the same results. From what I have read assigning users (ie your observer teacher) a role in a class and then clicking the eye checkbox when you assign them should hide them from view IF the viewer has the permission moodle/role:viewhiddenassigns set to prevent. I tried this and still found when logged in as teacher that these users with hidden assignments are still visible in the particpants list.
I found (as you probably did as well) this issue in the tracker http://tracker.moodle.org/browse/MDL-11343 It was closed, but I commented that I think it should be reopened.
Hope this helps--keep the forum posted if you find anything!
Tiffany
A possible solution might be to enable course guest access with the same enrolment key set for all courses. (It would not be necessary to enable guest access for the site.) Teachers could then be given the enrolment key and browse courses of interest without appearing in the list of participants. Please see the Guest role documentation for more details.
We had a problem with teachers being surprised seeing all these extra (system-assigned) people when going into participants.
Hiding them altogether I felt was not the best solution as we like transparency - teachers should know who can look into their course.
My fix which I've just come up with is very simple - change one default value near the top of the moodle/user/index.php file...
change
$roleid = optional_param('roleid', 0, PARAM_INT);
to
$roleid = optional_param('roleid', $CFG->defaultcourseroleid, PARAM_INT);
I think it is entirely justified to by default, show the default course role (instead of ALL roles). Now, teachers will have to specifically select ALL to see ALL. No scary surprises and no secret assignments.
Hiding them altogether I felt was not the best solution as we like transparency - teachers should know who can look into their course.
My fix which I've just come up with is very simple - change one default value near the top of the moodle/user/index.php file...
change
$roleid = optional_param('roleid', 0, PARAM_INT);
to
$roleid = optional_param('roleid', $CFG->defaultcourseroleid, PARAM_INT);
I think it is entirely justified to by default, show the default course role (instead of ALL roles). Now, teachers will have to specifically select ALL to see ALL. No scary surprises and no secret assignments.