Our intention is to not auto-correct searches. That is, we intend to completely respect the query you type in, and (in some cases) display a 'Did you mean?' link at the top when relevant.
However, there are a few outstanding major bugs in this area that we are working to resolve. As a result, you may see some auto-correct behavior in the search results.
Unfortunately, these bugs involve a bunch of APIs that are mostly out of our control. We are both working around these bugs and also working to get them fixed .
For some queries, it has been a little slow to resolve, but rest assured that this is a top priority. In any case, specific examples always help as we may be able to easily add more workarounds.