People vary. Things don't. There is, for instance, a standard width for doorways in modern houses. So if you have a model scaled according to Geep, or Poser 5, or whatever, that's what sets the size of the scene. The only significance to the scale which Poser defines is if you're set to use feet or inches or metres, instead of Poser Units, on all the parameter dials. And I know Poser 5 had settings which used Poser Units even when everything else used feet.