Public URLs expose read access
A public URL is a read exposure for a Collection. It can be unrestricted or restricted, and it can be a real public web presence. Write capability is not implied by the public URL itself.
Public URL != write access
Write access belongs to approved collaboration or invitation records. Do not treat the public URL as an editing permission.
Enable, disable, restrict, and request access
Public URL settings belong to the public Collection, not the account-wide private settings. Administrators can configure who can view and whether visitors may request read or write access.
People and permissions are administrator-controlled
Administrators can add users and manage access records for the public Collection. Public viewers can read according to the access mode, but admin-only controls remain unavailable unless the viewer is an administrator.