Quote Originally Posted by Jandor View Post
The echo can be used to peer at memories etched upon the aether of the soul, but that only gets a look at whatever that person is thinking about.
The Echo is not necessarily always viewing whatever someone happens to be thinking about. For instance when Fordola Echoes WoL's past she suddenly sees seemingly all of their adventures, and there are times WoL Echoes certain events that are unrelated to either a person or a location. Considering the Ancient's increased control of the Echo, it wouldn't be surprising if they could sift through memories at will.

Moreover, Emet does say that they can outright tell whether or not someone is lying. So while the Echo itself could serve to prove the point, it's also an aside.