here's something i need to test. to prevent AI pillaging can you place a worker and have them change the tile for one turn? they wont finish the new tile improvement but they usually get rid of the old one in the turn they decide to so. might be useful in mp to get rid of the tiles in the 1st ring around your better cities so the melee guys cant time their pillages to take the cities. only played a little last night but havent tried mp with this yet.