Spies can be important sources of information. In some cases, the PCs themselves will be the spies, infiltrating an enemy network to recover vital intelligence. But sometimes they will have to rely on information obtained by third party NPCs. In that case, you want to make sure you can trust your source. Because whoever heard of a double agent in a work of fiction?

Actually, it's been shown that in many universes, there are actually more double agents than just plain agents. So suspecting your spy allies of being double agents is often a safe bet. Unless of course it's even worse than that.

Transcript

Mon Mothma: So, like, oh em gee. The Empire has a built a new Peace Moon. Or whatever.
Mon Mothma: It's totally orbiting Endor.
Han: And where's that?
Mon Mothma: We think Endor is, like, a moon in the binary Endor System?
Han: Aha. Of which planet?
Mon Mothma: The gas giant Endor. Duh.
Chewbacca: Are there any celestial bodies in the Endor system not named Endor?
Mon Mothma: The stars are named Endor I and Endor II. That's, like, different, right?
C-3PO: Do you remember when I offered to help you name things?
Leia: This is your amazing scoop? Everything's called Endor?
Mon Mothma: Our best spy, Wedge, died to bring us this information.
Wedge: Actually, I'm right here!
Mon Mothma: Oh! Wedge, I totally didn't recognise you. Love your hair.