aakk9999 - 10:11 am on Sep 23, 2013 (gmt 0)
Yes, but if they do change titles it's because the algo has determined that there is something wrong with the title.
Not necessarily. I would say instead that Google believes their title is a better fit for that query.
I have seen that the same page sometimes shows the original title and sometimes Google-rewritten title, and this depends on the query.