Darcs is smart about your location in the current repository.... You can darcs
pull from any subdirectory of the local repository and darcs knows what to do.

However, if you specify a remote path to pull from other than the base of a
darcs repository, then darcs gets confused. Darcs should be *equally smart*
about finding the remote repository base.

If you have a remote repository 'remote/' and you run the command 'darcs pull
../remote/foo/bar/' then darcs should scan up the remote path looking for '_darcs'.

In short, if
    darcs pull ../remote/
will succeed, then
    darcs pull ../remote/foo/bar/
should *not* fail.

(Noticed on darcs 2.1.2)

I'm a bit suspicious of this feature.  

What if the remote repository live somewhere like
http://example.com/really/long/path/out/in/the/middle/of/nowhere?

Won't this mean it takes a good deal longer for darcs to figure out that
http://example.com/really/long/path/out/in/the/middle/of/nowhere is not actually
a repository (because it keeps hunting recursively up?)

Won't this lead to potentially all sorts of trouble with people who use nested
darcs repositories? (which repository did you mean to push to)?

I respectfully request that we wont-fix this.  I suspect making darcs smarter
about finding remote repositories will lead us to the kind of the bad place that
overly clever software tends to go.