Pfui - 6:00 pm on Nov 10, 2010 (gmt 0)
About the UA Mokita spotted --
Mozilla/5.0 (en-us) AppleWebKit/525.13 (KHTML, like Gecko; Google Web Preview) Version/3.1 Safari/525.13
-- the Help page was updated yesterday (editors must have been sleepy):
Instant Previews are page snapshots that are activated by clicking on the magnifying glass icon [img]; they allow users to get a glimpse of the layout of the web pages behind each search result, in order to help them decide whether or not to click a link.
Instant Preview[sic] are extremely useful to users and can help them decide whether or not to click on your site in the search results. You can, however, specify that Google should not display Instant Preview for your page, in which case neither the text snippet nor the preview will appear. ...
Source: Google's Webmaster Tools Help [google.com...]
Related (also updated yesterday): Removing snippets and Instant Preview [google.com...]
So if you want a snippet, you're stuck with allowing yet another Google UA, and a screen shot 'borrowed' full-time for on-demand.