Orange is the New Black, the series presents a variation on the prisoner's dilemma problem that is often discussed in mediation programs and texts. Piper and her former girlfriend Alex both have to testify against the drug kingpin they used to work for. Alex persuades Piper to lie and say she had no contact with the guy, otherwise he might take reprisals against them both. After giving her testimony, Piper finds out that Alex in fact told the truth at the trial, leaving Piper exposed to a possible perjury prosecution and an increase in her sentence.
In the prisoner's dilemma scenario, an opportunity to communicate as well as familiarity with the other player's past moves is supposed to allow each player to learn whether or not they can trust the other, and if trust is established, to encourage greater cooperation and mutually beneficial decisions. In the show, the two players did have an opportunity to communicate and also had a long history together. That is what leads Piper to trust what Alex was telling her and follow her advice. What she failed to consider, however, was that this long history should not have led to greater trust but instead to greater suspicion. In season 1 we found out that Alex had already played the defector card once, by betraying Piper and landing her in prison in the first place. In that situation, the parties' history and knowledge of each other's actions should have led Piper not to trust Alex again.
Piper seems to have such a strong need for love and acceptance that she trusts Alex even when she should not. I have seen it happen occasionally in mediation that a party develops (or previously had) warm enough feelings for the other side, that they make deals that they might later regret. Communication and trust are wonderful things , but nobody wants to be played for a sucker either. Sometimes it's a good idea to stay on your guard even while the other side is trying to play on your warm and fuzzy feelings. The way to test a deal is to consider not only whether the deal will work if the other side lives up to it, but also whether the deal makes sense even if the other side defaults.
That's a reminder that it is the lawyer's job to provide that kind of dispassionate advice. Piper's real mistake in this episode was failing to follow her lawyer's good advice, and instead listening to her untrustworthy friend.