git archive, cygwin, and --git-dir vs --remote

I'm using git on cygwin, and am confused by behavior from git archive.

git --version
git version 1.6.1.2

This command works as expected:
git --git-dir=/cygdrive/w archive --format=tar --verbose --prefix=tmp/
HEAD | tar -xpf -
The latest copy is retrieved and dumped to the tmp subdirectory.

However, I first went down the path of using the --remote option, as
described in the git-archive man page:
git archive --format=tar --verbose --prefix=tmp/ --remote=/cygdrive/w
HEAD | tar -xpf -

When I use the --remote branch it seems to create the same files.  But
then rather than exiting it hangs out until I kill the process, using
about the same CPU % as it did when creating files.

I'm trying to use this for a scripted build process where all I need
is the latest copy, not an archive.  And we're just starting with git,
so while it works fine now I think we're supposed to be switch from
shared drives to something more controlled, at which point I don't
know that the --git-dir option will work.

I've tried searching the mailing list archive, and got overwhelmed by
patches, so I apologize if this has already been discussed and I just
couldn't find it.