Maybe you were buffaloed. It took me a long time before I was confident about what I know(not that it is a lot). I always figured that every one knew better than me. But, once I started questioning people who seemed to be so sure of themselves, it was interesting to see them back-pedal and hem and haw. Next time you see them, just ask them what they mean by "Hertz vibration". You might be in for some entertainment!