writes "Google plans to make all published documents from Google Docs users crawlable, if the documents are linked from a public Web site. No official announcement appears to have been made, just a short blog post on the subject by a Google employee in a help forum. (One comment on the ghacks.net post linked above says that email was sent to the admins of Google Apps accounts.) There does not seem to be any way to make an individual document not crawlable; you can only un-publish it, at which point Web links to it will not work any more."
The move makes sense from one point of view — Google is just making crawlable a document linked from another crawlable document — but it's likely to catch a lot of people by surprise.