Corrected entry: After Dr. Scott exposes Frank + company as aliens, Frank replies 'Go on, Dr. Scott. Or should I say, Dr. VON Scott.' Brad is outraged, but it doesn't make much sense. Why would it be so shocking to hear that he has a German surname? He's spoken with a German accent throughout the movie. Simply stating his real name wouldn't imply that Dr. Scott is a Nazi. It is obvious that he is German. Richard O'Brien (creator of Rocky Horror) even states on the DVD commentary that he's always disagreed on this being in the film.
Corrected entry: When Brad and Janet's station wagon gets a flat tire, the light in the car is a bright white that is emanating from the floor (note the shadows above them and the ones on their faces). If the light was from the dashboard or dome light, it would be more yellow and cast downward shadows on their faces.