CPB taps pass rf and electricity when the faceplate is pulled. Just about all 1 ghz taps have this function. The problem with doing it the way your talking about is that you still see all the noise coming back from down the line. With the way he is talking about doing it, you only see noise that is passing thru the tap and going back. If you got a 20 db tap and the noise is 17 db, then there is no noise getting into the system.
This is CABL.com posting #334938. Tiny Link: cabl.co/mbzio