Curve 9300 on Prepaid Account it works but???

[xXxMissyxXx]

I have a unlocked curve 9300 bought off ebay. I have an AT&T account. I want to switch over to a prepaid account. I was told by a store rep that my BB would be able to call and text on a prepaid account no internet.

I popped my sim card (contract account) in the phone and it works. Internet, wifi and calling ...

I popped my daughters sim card in (pre-paid) calling internet and wifi works as well. Her account is an old account and I was wondering if it works because she is on the old prepaid $1 a day and unlimited calling to AT&T phones with pay per use internet or buy a package.

My question: Does the prepaid work because its grandfathered or does this phone actually work on a prepaid account?

[Mister Xiado]

Cellular data on BlackBerry phones is routed through RIM. If your phone is not provisioned on their side, no go. That's why it's a pain to use BBs with no data feature, and AT&T doesn't allow most BlackBerry phones to access WiFi without a BB data feature. Host routing table issue...

Long story short, if it works, hooray, but it's not supposed to.