Stephen Abrams of OPAC vendor SirsiDynix  talks government documents and relates his pet peeves about how governments use PDFs to hide information. As Stephen is Canadian, I'm not sure what government he's talking about, but some of his complaints sound familar to me:

3. Worse, let's create a 10,000 page PDF and try to ask any citizen to download and print that! If your report is too short to make it too big, just append all your data into the appendices and make it HUGE.

5. Place your PDF on your website and don't link it to with an index, table of contents, press release or some other finding tool. Make sure there are no links for the seacrh engine crawlers to crawl! You have plausible deniabliity and can say with a straight face that it's available on the web!

6. And my favourite government opacity strategy? Only place a minimum of metadata on the PDF on the web. Say, just a number like 1237D-f but make sure it's not linked to any real number and just represents a non-sequential accession number for the web file. Then it will be nigh on impossible to find it.

His other tricks make a good read too, but then I'd be reproducing his entire posting. He ends his posting with thanks to librarians and catalogers. Stephen doesn't usually talk about docs, he's more of a Web 2.0/Library 2.0 sort of guy, but his Stephen's Lighthouse blog is always interesting reading.