Introducing guest access for Office 365 Groups!

Delighted to clarify... A guest user is a group member. Apart from group owners, who can administer the group, there is no distiction between the rights of different group members. A guest user has exactly the same level of access to group files and the notebook as possessed by other group members. And yes, this means that a guest user can delete files from the library should they feel so inclined. Basically, don't invite guest users whom you don't trust - or segregrate documents that guest users need to access into specific groups.