Usually they do ship out at the designated date. But this being the product launch, the servers all under 'attack' with so many orders that overwhelm the servers, weird things do happen. Like confirmation emails not coming, until duno when then get the shipment email, or the weird last-in-first-out kind of orders and those who ordered 1-2days ago haven't got the shipment notification while those who just ordered 6hrs ago have gotten their shipment notice. Anything goes

Seems like Google's logistic team ain't as good as Apple's (maybe outsourced?) since Apple launch dun seem to have such issues although they still may have short supply problem.
if u want to confirm + chop get the shipment notice in 24hrs then keep re-ordering like other forummer said, if u get the shipment u can go cancel the previous order, but u risk they all get processed to ship at the same time and you cannot cancel it..