Why didn't Galadriel warn Aragorn that Boromir wanted the Ring?

[Galadriel55]

Originally Posted by Ivriniel

...and Maeglin's perversion through the promise of (oh god, I forget, was it Idril or Aredhel!).

Idril. Aredhel was his (dead) mother.

I don't think Galadriel was looking for "Sauronic" traits or influence. I don't think she was looking for anything. She was just showing each person to himself, playing the role of an external conscience. The person with a clear and doubtless conscience wasn't embarassed, upset, afraid, etc. In a way, she spelled out each person's dilemma that they may have been half-consciously hiding in their minds. She wasn't exactly tempting, but taking an existing temptation out in the open.