It is possible for a user to follow a group discussion and receive notifications of updates (including the text content), even though the user has not joined the Group.
I assume this is not intended, since a non-member will not be shown Follow icons on the group's home page. However, If the user clicks on a group discussion, it can be followed on the Discussion header page.
Need to remove the Follow icon on Group Discussions when viewed by a non-member?
updated by @lornawebber: 04/18/17 04:49:29PM