In a Google Webmaster Hangout from a week ago on Google+, John Mueller of Google was presented with a question on why some brands rank so well within the Knowledge Graph on Google.
Here are two examples of UK search results:
John basically said they should not. He went as far to say that "branded" results should not be ranking for these in order to ensure they do not become an "advertisement for a web site."
Here is part of what he said followed by the video answer which starts with the question at 52 minutes and 24 seconds into the video:
Here is a partial transcript:
That is kind of weird
In general, a lot of these answers work really well….
But I think, branded answers like that, probably not what we are trying to do here. I can definitely talk with the team here that works on that and see if we can improve that a little bit.
That is the first one I’ve seen where it is obviously branded like this, and that is something we need to watch out for. That it doesn’t turn out to an advertisement for a web site but rather that it brings more information to the search results about this general topic.
Forum discussion at Google+.