I’ve seen a few of these signs stuck outside meeting rooms today. They are a bit of a joke, aren’t they?
What do the interviewers suppose is going to happen should someone make a loud noise outside the meeting room? Do they suppose a marching band will come storming through? Do they suppose the interviewee will lose the thread of thought, then become disgusted with their potential new employers? I mean, why is silence any more important for an interview, than for a meeting?
One of those quirks of office life I suppose.