CritterNYC - 6:29 pm on Sep 2, 2011 (gmt 0)

There's nothing nefarious about it. Google doesn't need to crawl all your pages (regardless of robots.txt) to find the +1 buttons. You've got the JavaScript, from Google, right on the page. They just check referrers for the +1 to ensure it's been crawled. That's all.