From what I have read, the AT&T memo states,
Note: This modified return policy applies only to customers who purchase from AT&T stores.
The return policy for 3G is changing from 14 days to 30 days for both Apple and AT&T stores.
To cancel service within the first 30 days, the customer must return their equipment to the place of purchase (no exceptions).
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.
I guess if you buy at the Apple Store, no worries. We'll have to see if AT&T stores stick to their guns.