Yeh, crazy isn't it Missy. I guess the laws of physics in relation to Wake vortices and what they can do to a light aircraft cease to exist in E airspace. Why... cos Dick says so thats why! I also assume that if the Virgin 737 had hit severe turbulence as it overflew the lightie by 600 ft (or 400ft whatever it actually was) and could not maintain altitude, that would have also been ok. And I also guess that since the 737 mode C could legally be 200 ft incorrect from what is displayed when verified and IF the lightie also had his mode C verified it also could be 200ft out, that this still isn't a problem in E airspace. Guess all these reasons we have a 1000ft and 5NM standard again cease to exist in Class E airspace.