with so many phones pre-ordered, one has to wonder if there will be many phones left for sale on launch day. AT&T has already stated they wont even have any phones available for pre-order until the 29th. apple has stated that they are filling the pre-orders first so, how much is left for the stores? anybody's guess.
I think folks that camp out make this a fun event. This has sort of become a yearly event, some might even call it cultural.
No one really knows how many phones beyond the pre-orders that Apple took. The should fill pre-orders first. Still I am pretty sure Apple stores will like have some supplies of phones for walk-ins.