Can I temporarily use an iPhone 3G on a 2G plan?

[iObama]

Hey guys -

I just sold my iPhone 2G on eBay, and my mom's willing to loan me her 3G for a few weeks while I finish saving up for a 3G S. I tested it earlier and my SIM does work in her phone to make calls and such.

BUT... will AT&T find out and charge me a higher 3G price for temporarily using the phone's 3G networking? I'm only going to be using it for around 2 weeks.

Thanks in advance,
iObama

 

[Applejuiced]

You should be fine just for 2-3 weeks.
After months they might contact you though.

 

[ejrizo]

I have done this since July of last year with no problems. They do text me every so often saying my plan is not compatible and to call them. I never have and still get charged the original plan.

 

[aerospace]

What did you get for the 2g?

Also has anyone tried this with 2g go phone plan? I'd love to keep paying $49/mo instead of $69 + $15-20 in taxes and fees plus no texts included. Of course I'd have to buy the phone off ebay but it seems cheaper in the long run.