FWIW, I spoke with the manager at my local AT&T corporate store who told me that I would NOT be able to purchase iPhone 4 at an Apple store on via Apple online with the FAN discount still attached to my account. Now maybe he was just trying to make a sale and avoid having a potential customer buy elsewhere, but after going through that experience two years ago, I'm just not going to risk it. Besides, what is the downside to taking the FAN off temporarily? Maybe a gap of a month or so for it to get reflected in my bill again, but that's it.