Eagle eye and fellow EI, Chris Selland, points out this plausible scenario.
In spite of numerous Apple threats, lots of buyers, particularly overseas ones, never triggered their AT&T service which with the first iPhone could be done on the web. With the 3G version, AT&T will only sell them with in-store activation.
But check out this memo to AT&T stores leaked by Gizmodo "If the customer cancels service after 30 days, they will be charged the ETF. The customer is not required to return the device to cancel after 30 days."
ETF is early termination fee - should be $ 175. Since you have to keep it at least 30 days you end up with the cost of the base voice and data plan and taxes for about $ 75. Since the new 8GB version is $ 200 less than version 1 in effect AT&T is subsidizing those that want the new iPhone and plan to use it with WI-FI or try to hack and use with other mobile networks.
So, worst case scenario - AT&T store costs skyrocket as everyone has to go in to activate, and a large percent cancel after a month and sell on eBay. Or buy for their friends overseas since even at $ 500 (phone for $ 199 + ETF of $175 and first month at $75 plus taxes of say $ 50), with the way the dollar is, the US version will likely be a bargain compared to many other parts of the world.
Readers, can you drill holes in Chris's gotcha?