I'm playing a game right now where I've never had so much spy-activity! It's not one of my best games; I'm Japan and at the beginning of the modern age and most others are almost done with the industrial age.
First the Byzantines kicked out a spy of mine in Constantinople. Next turn they attempted to steal my world map, but failed. So I figure, perhaps this is the right moment to plant another spy in Constantinople: success! Next thing I hear is that there's Byzantine propaganda in a former city of them, so they have a new spy in Kyoto! And so a safe attempt to kick that one out succeeds.
Have you ever experienced this behavior before?