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Originally posted by: Darth Chaltab
Nobody trained Quigon in how to do this, so perhaps Vader discovered it the same way QuiGon did.

Maybe, but it seems unlikely.

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Obi Wan knew of Leia, he just did not consider her a "Hope"... Obi Wan didn't think she could be as effective against the Emperor as Luke was.

Like I say, it's open to interpretation. I maintain that it comes of as if Obi-Wan is ingorant of her existence. I also maintain that this makes more sense.

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Actually, it makes more sense that way. After all, R2 is the hero of the series, constantly saving everyone's butts, and he understands how important it is to find ObiWan and all.

I don't think that remembering what transpired before has any impact on Artoo knowing how important things are. However, it definitely seems to me that a droid rolling around with that much super sensitive knowledge in it would be a severe security risk.