AT&T Unlim data family plan question?

[Volerikan]

So right now I currently have 2 iPhone 4s on a family plan, mine is unlimited data and my girlfriend's is slightly newer with only the 2gb option.

Would I be able to activate a iPhone 2g with her number in iTunes? And does it automatically switch it over to $20/2g unlimited? Or do I have to call?

Then I would have her use it for a week, switch the sim back into the iphone 4 and she's good to go with $30/unlimited?

I'm sure I'm missing something, sounds too easy.

Am I able to use a micro-sim in the 2g if I have an adapter?

Please answer, I'm about to go on eBay and get a new 2g. (my old one broke then my ex stole it x.x)

[souljerr]

u would have to call for the switch but its really easy to do honestly just say u had to get the iphone 4 repaired and ur stuck using the 2g and theyll fix it for u. then call back to do a sim swap and theyll need the imei for the iphone 4 and tell u the available data plans and the 30 dollar one is available

[i.Annie]

There's a rumor they're cutting off unlimited data even for current users who have it. Not sure if it is true, but just letting you know anyhow.