"Data Plans: An eligible data plan is required for certain devices, including iPhones and other designated smartphones. Eligible data plans cover data usage in the U.S. and do not cover international data usage and charges. If it is determined that you are using an iPhone or other designated smartphone without an eligible data plan, AT&T reserves the right to add an eligible data plan to your account and bill you the appropriate monthly fee."
http://www.wireless.att.com/cell-phone-service/legal/plan-terms.jsp
In other words, if you dump your iPhone for another device (remember a handset that supports data is a smartphone, just uses a non iphone plan, like a samsung phone or android device, etc)... so yeah, they're covered. And only people eligible for iphone upgrade are those on upgrade, so yes, they're contractually allowed to cancel your upgrade eligibility for swapping sims.
You sir, owe me $10. Will that be cash or PayPal?
People, it's 10 days till you'll have the iphone in your hand, don't risk it!
please just stop posting. seriously. you are spreading wrong information.
thanks