I think many(?) of us do this because it functions the same as doing the alternative for becket left/CW dances: it gives the dancers a clue as to which direction they will progress in the hall. They line up improper, looking toward their direction of progression, and then they're rotated consistent with that for the dance's becket orientation.

When I call, I'll often include a little tip on that as we begin the walkthrough - "this is a Becket Right dance - what that means is, if you look to your right currently, THAT will be your direction of progression."

-Don