Keyboard dock: the blank key

A (PC) friend recently asked me "why would Apple make the iPad keyboard dock with a blank key?". to him it seemed that Apple wouldnt put a blank key on its keyboard for no reason. He then quizzed that maybe its for a feature yet to be revealed. If he's right what would that feature be? I'm speculating it would be a multitasking button, that would explain why it was left blank, so not to reveal this iOS 4 feature at the iPad launch. what do you guys think? is it simply a space filler? or is there something more sinister going on! hehe

Message was edited by: wildcat1559