e.g. http://www.cnn.com/2016/08/15/us/gabby-douglas-natalie-hawkins-new-day/index.html (May have to sit through an ad, not all CNN videos have CC.) I noticed this video had closed captions automatically shown. I thought that was a strange choice by CNN, but noticed this isn't happening in Chrome.
I have noticed that a large number of sites are opting in to show closed captions because people don't want autoplaying videos with audible sound, but may want to watch the video and read the captions. My anecdotal evidence is of videos with the captions burned/encoded in to the video frames.
I've opened that CNN URL in Chrome and also got automatic subtitles (at least with HTML5, I've disabled Flash).
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