I'll go even further than that. IETF does not believe in PDF.
All drafts discussed in this group must be available in ASCII. It's
fine if people also want to provide PDF versions of those drafts, but
the ASCII version must be definitive, and it must contain all of the
information that is in the PDF file.
Otherwise the people who don't have PDF support will be isolated from
the discussion.
As for line numbers -- they do get in the way, but numbering sections
and if necessary even paragraphs is just fine.
Keith