first thing that made me suspicious of her, was
when she first woke up, and Hurley was beside her, pretending to call his mom throught her satelite phone (

)
Hurley saw her waking uo and started asking questions like there was no tomorrow
so he asked who she was, how she got there, why was she there, ....
and she was quiet and then just said, Who are you
when he said they were 815ers, she was like "No way, 815 crashed with no survivours)
I mean, besides her dodging his questions, would you, an average american, remember the number of a flight that crashed 3 months ago??? i mean, the plane crash maybe, but the flight number?

?