Google is essentially clicking every link on the page -- including links like "delete this" or "cancel that." And to make matters worse, Google ignores the Javascript confirmations. So, if you have a "Are you sure you want to delete this?" Javascript confirmation behind that "delete" link, Google ignores it and performs the action anyway.
We discovered this yesterday when a few people were reporting that their Backpack pages were "disappearing." We were stumped until we dug a little deeper and discovered this Web Accelerator behavior.