I just chatted with AT&T support about this, see chat below. But everyone here on this forum I see doing this says it's worked for a long time and I see no instance where AT&T swept their account and added the "required" voice plan. Any experienced response out there?
me: ...
agent: I want to make sure that I understand. You are asking if you can put an iPad microSIM in your iPhone to use a no-contract data plan on. Is that correct?
agent: It might work for a bit, but the system routinely sweeps and it would be noted.
me: I see. So do you have a written policy that specifies between which devices a sim may be swapped?
agent: Thank you. Please bear with me for 2-3 minutes.
me: Sure, no rush, thanks
me: And when you say the system sweeps and notes this does that mean service is shut off, or just noted?
agent: Legal Terms for your AT&T contract.
me: Thank you
agent: The system sweeps and adds the required plans.
Well, it is AT&T, so you can never put it past them to behave anti consumerist that is in the genes of their namesake. So I guess they 'could' do system sweeps much as they do to keep smartphones off their network that don't have a data plan.
But, that was not my experience during the months that I did this off-and-on for the last couple of years. I just tired of the performance of AT&T's "3G." If you already have an iPhone and tried, the most you could possibly be out-of-pocket is the remaining data for the month that you prepaid before getting turned off. And then you could just walk right back into an AT&T store, get a new free sim card, and setup ANOTHER account. Seems like too much whack a mole for AT&T to follow through doing system sweeps. And after all, you're getting nothing more than the service you paid upfront for. I just think the online rep you chatted with is ill-equipped to deal with such rare questions.