No. It is sufficient to prevent casual copying of executables, but
    software exists which will allow any user to copy X flagged files.

    The X flag cannot be removed from files, so it is is a good measure
    against computer viruses. However, virus scanners cannot read X
    flagged files, so infected X flagged files will be difficult to
    detect.

    Wolfgang Schreiber wrote a utility called X-AWAY, available from
    ftp.novell.de, which enables a Supervisor equivalent user to copy
    X flagged files. X-AWAY is deliberately crippled to prevent
    non-Supervisor users from copying programs.