Mailbox Full Access (RW)
Grants members FULL mailbox access to all content within this mailbox, including the ability to manage all calendar content (delete, edit, create).
Calendar Read only (Reviewer)
|Grants members of this group the ability to view details of the calendar items only. No ability is granted to book this resource nor to edit any existing content.|
Calendar Direct booking (Booking)
Grants members the booking policy permission, which allows them to send calendar requests that will get auto-accepted so long as it doesn't conflict with other meetings on that calendar. Also allows members to do availability lookups against the calendar.
With these settings members of the booking group invite the resource to a meeting and, if there are no conflicts, the resource will auto-accept.
If you do not want your booking group's members calendar requests to be auto-accepted members of your RW groups are able to make these changes.