In Libation Bearers, trickery is the main weapon the powerless can use against the powerful. At the very beginning, Orestes asks the god Hermes to be his "saviour and ally" (Fragment 1, 2). It makes a lot of sense, because, among other things, Hermes is the god of trickery. None of the characters, even our heroes, are above lies and deception. Orestes and Pylades pretend to be Parnassians, in order to get into the palace. Even more strikingly, the Chorus, a group of slave-women, becomes a crucial player in the action when they convince the Nurse to trick Aegisthus into leaving his bodyguards at home when he comes to meet the "strangers." Yes, it seems that Hermes was the right god to call upon. All of the major action in the play is powered by trickery.
Clytemnestra is the best at seeing through trickery in Libation Bearers. This reflects the fact that she used to be the greatest trickster (in Agamemnon).
Orestes is the best at seeing through trickery in Libation Bearers, because he never deceives himself.