Well Queen I don't think that Desmond had the power of forsight (and know it at least) until after he turned the failsafe key... Just my opinion I really don't have much to prove it, just that when Charilie wants to know what happened to him is when we found out "for sure" that he could see the future

But really I guess it is just my opinion

__________________
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.