In OS X NSEvents are generated when the pen is close to the surface already, so a program knows where the pen is before it actualy touches the surface. Windows works the same. AFAICS iOS doesn't: looks like UITouch events aren't generated until the Pencil actually touches the screen. Is this corrrect?
Does Pencil generate proximity events?
On iOS, there's nothing to correspond to "Touch not yet started" in the event types.
Or were you trying to ask a question directed at someone who might have the new hardware and not be under NDA concerning its behavior?