[UPDATED: the store manager will tell people how many iPhones are coming in the second shipment.]
Just got a leak from AT&T Ninja about Tuesday's iPhone 4 shipment to retail stores. Apparently, the shipment is coming in two waves, with an early one Monday night that is expected to sell out quickly and a stealth 2nd shipment Tuesday between 10:30 and noon. The store manager will [not] wait until all the iPhone 4s are gone before telling the people in line that a second shipment is coming. They'll take "reservations" from the people still in line when they sell out, so they're suggesting people stay in line in case some of the people in line don't buy because they don't have upgrade eligibility or they're over their limit on their credit card… what the document calls "fallout."
They are also setting aside 2% of all the phones they get - half 16GBs and half 32GBs, for "customer escalations," presumably this means phones that customers bring back and want replaced.
An inventory report will be available Monday afternoon to the store mangers that will indicate exactly how many iPhone 4 (16GB and 32GB) they will receive in their Monday and Tuesday shipments. The manager is to subtract 2% with a 50/50 split of 16GB and 32GB. This will provide some inventory for customer escalations.