I've noticed it often means they are/will be going into war mode with you. It seems weird because this happens even with open borders, where they are free to scout and get your layout in a much more nonchalant way. I know its not always the case, civs also seem to want maps post-Optics when they are scouting to circumnavigate and colonize. Still, I've noticed a pattern that aggressive civs will ask for map, then go into WHEOOHRN (if they weren't already in it), suddenly there's a stack at your border. The only logic I could put to this is that the AI wants to select a vulnerable city to attack since the map reveals all cities at once. For this reason I generally don't give out my map (and to get the +1 ship movement!). As a trading chip it usually only carries 5 or 10 gold value and I just don't see any reason not to keep the competition in the dark. Has anyone else noticed this or am I ?