A blogger got hold of a secret un-released HTC One phone. He did a video in mid Feb reviewing the various features and at the same time showing the IMEI number. For reasons unknown the video was just posted (3 Mar) public on YouTube. One person re-posted to several other places and it got re-re-posted. Until it reached the ears of the Corporate Communications Manager.
HTC Comms Manager on phone video leak.
The aftermath. Not too sure if it is real, his parents lost their jobs.
HTC One phone video leak aftermath
In general, new products are tightly protected under Non Disclosure Agreement (NDA). For media, traditional (newspaper, magazines) or new (bloggers), the NDA comes with a time controlled embargo. The new products are shipped to them up to 2 weeks to 2 month before planned release so that they can review and put to print. Anyone breaking the NDA are liable to serious financial penalties and/or future blacklists.
So all media outlets play ball and very seriously, after all no one wants their entire firm to be blacklisted due to the mistake of a single person.