although siuan can see ta'varen I'm surprised she didn't see rand's birth, like the Amyrlin that Moiraine and her were attending does.She was right next to her and later in the series it seems that she sees ta'varen in a bright light much like the light of Rand's birth the Amyrlin saw. And Lan did lie for Moiraine, that was one of the duties of Warders. Egwene notices this when she had her dilemma with bonding Gawyn.  I think Warders were created just  because the sisters needed a way around the three oaths.

Is Narg the first Trolloc Rand kills?