I can see her tricking the Straw Hats into believing she was some helpless, lost child. But providing Zoro doesn't go brain dead for a while he might point out that she looks familiar.
We don't really know how much of a trickster she is, or if she can even be trusted. I would hope so, because we already have one person on the ship that we need to worry about, and we certainly don't need another.
R.I.P food supply though, at any rate.