Robin doubts that the fortune teller knows what's really happening with Phalanx. She isn't a clairvoyant or a true mind-reader. She just has one subtle, magical trick that she uses very, very lucratively. And on top of that, she really is blind, so she can't see the way Phalanx subtly changes colors as they're talking.

"Didn't want what, dear?" She asks politely, from her side of the table. Robin lets her ask, because he genuinely believes she would not be able to glean enough to do any harm. At least--not on purpose.