I don't think this is very accurate. All other multilateral IPR negotiations are far more transparent:
http://www.keionline.org/misc-docs/4/attachment1_transparency_ustr.pdf

I agree. A call to a Congressman's office from a constituent actually means a lot. They don't hear from anyone but lobbyists on most issues.

I think this explains in part why Yahoo has focused so much effort into getting WIPO to create a new global treaty on webcasting. Unfortunately, that's not good news, and my guess is that few people actually doing technical stuff at Yahoo even understand how messed up the webcasting treaty langauge is, and what it would do to the web.
More on this here: http://www.cptech.org/ip/wipo/bt/

Jamie