Mirrors not tracking main ftp site?

On hub, in /home/projects/pgsql/ftp/pub/dev I see

*.tar.gz.md5                            postgresql-opt-snapshot.tar.gz
doc                                     postgresql-opt-snapshot.tar.gz.md5
postgresql-base-snapshot.tar.gz         postgresql-snapshot.tar.gz
postgresql-base-snapshot.tar.gz.md5     postgresql-snapshot.tar.gz.md5
postgresql-docs-snapshot.tar.gz         postgresql-test-snapshot.tar.gz
postgresql-docs-snapshot.tar.gz.md5     postgresql-test-snapshot.tar.gz.md5

which agrees with the view at http://www.ca.postgresql.org/ftpsite/dev/.

However, it seems that the mirrors have a lot more stuff:
ftp://postgresql.readysetnet.com/pub/postgresql/dev/ shows dozens
of files back to 7.1beta6, and so do the other several I checked in
a random sample.  Is the update mechanism failing to cause old files
to be removed from the mirrors?

Also, some of the mirrors claimed to be up-to-date by 
http://www.postgresql.org/index.html aren't. Fr instance,
download.sourceforge.net doesn't have 7.1.1 nor 7.1.2.
I thought that the up-to-date check was automated?
        regards, tom lane