so I bypassed activation with iAsign on my downgraded 1.0.2 phone. Popped out my SIM, and put in a different AT&T SIM from one of my family line phones. To my surprise, the phone acquired signal (the SIM was an old 32k cingular SIM) and the display even showed "cingular".

So according to this, can we infer that:

If you are an AT&T customer, you can upgrade your phone to 1.1.1, and just register your phone as a go-phone, once the phone is activated, you can just swap the SIM out to your old AT&T sim and have service??