How???

So I have a question, how is it that one can lose a cell phone within a month of getting the new phone? Mom can't locate hers, and when I checked the online usage w/ AT&T she didn't even use it yet this month.. I don't get it. I checked her car last night (the car bit me when I checked under the seat... damned auto seats!) I tried to call but naturally the phone is either off or dead. The good thing is that we live in a small place, there are only so many places to hide!