In 2011 Stan posted a video of Tom Hanagan talking about the old-style versus new-style windows. It suggests the flap on the older models was needed to avoid leaks....
Also- As several others have noted, I too have had the problem of wind-blown rain soaking through the lower window-stitching on my 01 Hawk. It has only happened once so far and only on the windward side of the camper in a driving rain (with the exterior flaps left up). But that was enough to tell me I wouldn't want to just cut them off.
Edited by Old Crow, 11 June 2017 - 05:01 PM.