Yeah, I've often wondered about that text...
(3) Briefly describe the review of this document that was performed by
the Document Shepherd. If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.
I've always assumed it means "If you are forwarding this to the IESG without it
being ready for publication, you have a lot of explaining to do."
Adrian