Can't suppress "good signature" status message

[Skip Montanaro]

I run gpg as part of a shell script which runs from cron.
I would like to suppress or redirect messages which are
"status good" and only emit messages to stderr which
suggest there was a problem with the script.  (I get
enough mail as it is.)  I have so far been unable to
suppress the "good signature" message:

    gpg: Signature made Fri Nov ...
    gpg: Good signature from ...

I am running gpg (v 1.4.11) like so:

    gpg --status-fd=4 --no-mdc-warning \
        --no-secmem-warning --quiet -d ...

The use of status-fd, no-mdc-warning and no-secmem-warning
suppresses or redirects everything else which I expect.
Replacing  status-fd with status-file had no effect.  The
"good signature" messages still appear.  The script is run
with fd 4 redirected to a file and we know to look there if
the cron job fails.

Reading through old posts I saw various recommendations to
use status-fd, status-file or to redirect stderr to stdout
and use grep -v to eliminate those lines.  The status-fd
and status-file flags don't work as far as I can tell, and
as also noted in an earlier thread from 2009 there is the
risk that using grep you might eliminate something useful
(low probability, but not zero).

It seems to me that the display of this message is somehow
not done through the proper channels.  GnuPG appears to
already have about 37,000 command line options, including
options to suppress or redirect all sorts of stuff.  Just
not this. Maybe it needs another option. :-/

Skip Montanaro