This has nothing to do with with leaving early, which is totally fine as long as you do so politely and decently as what you are actually doing is saving the in

This has nothing to do with with leaving early, which is totally fine as long as you do so politely and decently as what you are actually doing is saving the interviewer from wasting time and effort. No, this is to do with embarrassing and humiliating the interviewers in front of the other candidates. The example guy stood up and walked up in front of every other candidate and sent a clear message to them all. Having stuck his neck out he slightly undermines himself by showing he was not aware of how he got in to the room in the first place!!!! Like I say, if done right you are doing the interviewers a favour by leaving as soon as you are clear you don't want the job. How you do that is every thing.