Let's say a Soviet exchange student back in the '70s would go back and tell the KGB about people and places and things that he'd seen and done and been involved with. This is not really espionage; there's no betrayal of trust.
“Mars, when guilty of homicide, and set free from the charge of murder by the Athenians through favour, lest he should appear to be too fierce and savage, committed adultery with Venus.”
“Should we have background checks, waiting periods? To drive a car you have to pass a test that shows you know how to drive your car safely, you should have to do the same thing with guns.”