Sagamore Google Drive
Documenting how Sagamore Hills Elementary School can use the Google Drive service of their PTA's Google Apps account…
Adding files
Log into Google Drive as admin@sagamorehillspta.org and upload the file(s) into the top-level "Sagamore Hills Elementary School" folder.
This way, the file will be permanently stored with the PTA (not at the mercy of volunteers) and only admin@sagamorehillspta.org can delete it.
Also, the uploaded file(s) will inherit the sharing permission of the "Sagamore Hills Elementary School" folder, which is to allow the group (which contains all volunteers) to edit the file(s).
Theory
The idea is that all files are owned by the admin account, which is hosted by the Sagamore Hills PTA Google account, so that storage and deleting are under organizational control. All files also assign the highest level access (edit access) to the Sagamore Hills PTA Google Group, to which all volunteers are a member so that any volunteer can edit files (old versions remain available and cannot be deleted (except by the admin).
Volunteer personal (or not) Google Accounts are added and removed to/from the Sagamore Hills PTA Google Group to allow/disallow working with Sagamore's Google Drive hosted files.
A single folder named "Sagamore Hills Elementary School" contains all files (and folders). This top-level folder is assigned the previously mentioned permission, which become the default share setting for new contents added to it. Volunteers will know to go to this folder in their own Google Drive environments.
Although volunteers can add their own files to the Sagamore managed folder, those files should eventually be uploaded again through the admin account so that they can be owned by the PTA (stored by, deletable only by, controlled by).