We successfully used the online course request module for our academic courses last spring.  We are currently giving the course request module a try with activity (clubs for us) sign up.  One thing that is troublesome is our "hidden" groups.  When we use the online request module, students see ALL of the groups they are enrolled under the "Selected requests" even if they are not given access via the group page access to view the group.  It would be very helpful if we could truly "hide" some of the groups from the online sign-up.  Support provided me with a tip to make the activities "Inactive" so that they would be unable to sign up for them which is great to keep the list of available clubs appropriate, but students can still see those enrollments even though they are inactive and there is no group page access given.