When creating a group in ArcGIS Online (Organizational account) that has group members able to update items, a Level 1 (non-edit) account cannot be added to the group. As a result, we have to manage two groups. In some cases this may be the best option, however often this is overkill.
It would be good to be able to add Level 1 accounts to groups with update of content enabled, while honoring individual users privileges. This would allow users that can edit to edit group content while users who can't edit still can't edit, but can join the group to view content.