What do users who are not logged in see? So, if the field is only visible to admins, then I would expect that users would not be able to see it even after logging out, correct?
Is there a reason why you chose the text field for the group setting instead of a group_list? It’s a bit more convenient for entering groups because you can select them instead of typing the name. However, it works with the ID, so you have to change the code a little. But it still works even if you rename the group.