The MotionPlus is quite the tool. It can provide a very accurate estimate of where the pointer is when offscreen. The best way to see this tracking in effect is by looking at Zangeki No Reginleiv, a wonderful game made by Sandlot, the geniuses behind Earth Defense Force.
You can clearly see that not only does the game know where the pointer left the screen, but how far away from the screen it has gone. Hopefully Conduit 2 will use this to boost camera speeds when turning.