Hm, the article several times says "required not to be indexed", while robots.txt is more like "request not to be crawled".
An important distinction, because a page may well be indexed without being crawled, typically when there is a link to it. Better to use the noindex meta tag (at least if you are only concerned with search indexes, not access control).
Yes. This need to be emphasized:
Disallowing URLs in robots.txt will not necessarily exclude them from search results.
Search engines will still find those pages if they are linked to or mentioned somewhere else.
The search result will consist only of the URL, and the snippet will say "A description for this result is not available because of this site's robots.txt"
Use the noindex tag, folks. Also, Google Webmaster Tools allows you to remove URLs from Google's index.
