The NSS file system on OES the NTFS file system on Windows servers, and the SharePoint Document Libraries on SharePoint servers always control access to the files and folders they contain. Users seeking access through a file browser, such as Windows explorer, must generally have the required permissions on the file system or document library to gain access.
This is absolutely true when accessing files and folders through Filr. You cannot gain more access through Filr than the underlying file system or document library allows.
Sharing through Filr is no exception. Obviously, users must have access to files and folders in order to share them, and they cannot grant a higher shared-access role than they have.
Shared access to files and folders in Net Folders and Home Folders depends on the Net Folder proxy user having the required file system or document library rights.
Shared access to folders and files in Personal Storage is controlled by the Filr system itself because the files and folders are contained in Filr-based storage.