Just before the dramatic collision between the two groups; the hostess disappears all of a sudden; and noone mentions about her anymore; doesn't it seem a bit weird?

Not at all, I would expect you will learn a lot more about Cindy's fate in a couple of months - and whether or not her disappearance was part of the plan, or just another Lost mystery.

__________________
"The Naked Gun!"

Frank Drebin remembers a lost love.

Frank: It's the same old story. Boy finds girl, boy loses girl, girl finds boy, boy forgets girl, boy remembers girl, girls dies in a tragic blimp accident over the Orange Bowl on New Year's Day.

Jane: Goodyear?

Frank: No, the worst.

Thanks for the comment Lizard2112; in fact, what I've found weird was not the sudden disappearance of Cindy (her name was that, I presume); but rather, that noone mentions about her again. On the other hand, whenever a fella disappears or falls into danger, almost always someone comes out with a helping hand (there are many examples). Noone seems to care about poor Cindy, eh?

Maybe their minds were too busy with Shannon's "collision" with Ana Lucia; Sawyer's condition and stress between Sayid and Ana Lucia...

I heard she shows up later in the Others' compound when Jack, Sawyer, and Kate are held prisoner, but I don't know for certain.

Yes Cindy just disapeared on the way to the beach camp with the tail survivors while Sawyer was on the strecher and pulling him up the "wall" for lack of a better term, she disappeared.. Then she shows up while Jack is in the cages with the to kids Zack and Emma (I think) and said "We're here to watch" Then we see her and the kids again in the others camp when John Locke was with them and supposed to kill his father.. That was the last time we saw them I think

__________________
Please don't give up, Des. Because all we really need to survive is one person who truly loves us. And you have her. I will wait for
you. Always. I love you, Pen

DESMOND: I love you, Penny. I've always loved you. I'm so sorry. I love you!
PENNY: I love you too.
DESMOND: I don't know where I am, but--
PENNY: I'll find you, Des--
DESMOND: --I promise--
PENNY: --no matter what--
DESMOND: --I'll come back to you--
PENNY: --I won't give up--
BOTH: I promise. I love you.

That darn Cindy is a mystery!

__________________

`Dear, dear! How queer everything is to-day! And yesterday things went on just as usual. I wonder if I've been changed in the night? Let me think: was I the same when I got up this morning? I almost think I can remember feeling a little different. But if I'm not the same, the next question is, Who in the world am I? Ah, that's the great puzzle!'

-- Alice, from “Alice’s Adventure’s in Wonderland”