In my dblog occassionally I am seeing query coming probably from search engines for links as

http://mydomain.com/node/13130/delete?destination=node

I wonder how possibly search engine got idea to query that kind of links (of course those links are not exposed to anonymous users)

I have xml sitemap installed but no such links exists in the index

When I query google for that link, I see that link is present in index (of course clicking on that link leads to access denied page), and also shows

A description for this result is not available because of this site's robots.txt