Someone else's data?

[BroncosMom]

Friend of mine has a Samsung Impression and she went to go to Facebook's mobile site on her 3g network with AT&T and it logged her into someone else's account as if it had been previously logged in. The name on the account belonged to nobody that she knows and her phone wasn't out of her reach since the last time she logged into Facebook. Is it possible to pick up someone else's data information over the network? You know like when you used to be able to pick up interference on phones? I'm curious if any of you cell phone whiz people might have any ideas? She's nervous she got a junk phone. I've tried to show her the light of the BlackBerry but she's not coming to my side of things!