I think the numbers are skewed
Here's my experience from yesterday:
Went to att.com to order yesterday at 6 AM EDT. Made it through all the screens in about three minutes, entered my credit card info, and clicked "Place Order". My browser sat there for about 60 seconds and then I got a message that it had timed out. No confirmation screen, no confirmation e-mail. When I tried to check my orders on att.com, it said I had no orders.
Thinking that the order didn't go through, I tried again several times on att.com, and at about 2 PM EDT, I was able to place an order and get to a confirmation screen with a number, which I printed. About 30 minutes later, I got an e-mail informing me that AT&T had cancelled this order.
At this point, I downloaded the Apple Store app and reserved a phone at my nearest Apple Store that way.
About 6 PM EDT last night, I decided to try again--this time at apple.com. After three or four attempts, I was able to add a phone to the cart for 6/24 delivery and checkout. I received the e-mail confirmation from Apple, and figured I was all set.
This morning, I woke up to find that AT&T charged my card $212.93. I went to att.com and it was now showing that I have an order (that is not backordered) consisting of a 16 GB black iPhone and a SIM card. Since there was no way to cancel the order on AT&T's site and they had already charged my card, I went to apple.com and cancelled my order there. I received an e-mail stating that because I had cancelled my order, I would not be charged.
Keep in mind that all of these different orders and reservations are for one line of service. I suspect I could've left my order on apple.com in place and I would've had two iPhone 4's at the subsidized rate delivered to me on launch day.
Until I get a shipping confirmation from AT&T, I am keeping my reservation at my local Apple Store for 6/24. I suspect a lot of other people are potentially in the same boat as I am after yesterday's debacle -- multiple phones coming to them from different places.
If many people receive multiple subsidized phones on launch day, they'll sell the extra phones on eBay and make a couple hundred bucks per phone, most likely.