[ChuckElias]

Snake, it's more like the OLD high school mechanics, where you had a "normal" position, and a "reverse box" position. You always box in at the beginning of the play, but if that put you in the "reverse" position, then the Lead and Trail would both switch sides of the court in the middle of the play to get back to their "normal" position.

So if the ball goes OOB on the "wrong" sideline, the Trail goes over to administer the throw-in, but then crosses the court during play to get back to his/her correct sideline.