Ah, that might explain something in my most recent game I was puzzled about - I'm the only civ left on my continent, Askia and Elizabeth are on the other one. Yet recently Askia warned me about massing troops near his borders! I had all my troops on my continent, my navy on alert round my coastline, several hexes away from his. However he had a frigate out on patrol, and a scout embarked, both passing my coast. Christ, there's some idiotic bugs got through testing!