The big question is when you order at 12:01 am is that for shipment or pickup at the store? If you are able to reserve them for pickup will there be any reserved for walk-ins that did not order online? Otherwise if they sell out early in the am online for pickup and shipment the people that wait in line may not get anything.
I was thinking the exact same thing. If I don't find out a definitive answer before the 20th (which I'm sure I will), I will try to pre-order (for in-store pick up) at 12:01am, while I am standing in line in front of Apple Store.