I just razed two of my enemies cities, and as a result they got 8 free riflemen. One of them was a new city that they've built in the last 5 turns. This is a lot faster than building all these riflemen by yourself. So in multi-player games, is it possible to create a few settlers, have a friend declare war on you and raze the new cities as you settle them. That way you get a bunch free units that you can use to attack another enemy. You make a deal with your friend that you won't attack each other, and maybe later you can enter into a permanent alliance so you both can win.