The game I'm working on is peer-to-peer, and some movement predictions will be accurate because some movements will follow a predefined sequence.
My game is a fighting game. Example of "easy-to-predict" movements: parabolic jump, throwing fireballs, special moves. That's why movement prediction will work well in some cases.
If you can get roughly the latency both ways, couldn't you then assume that the connection is asymetrical and using the average download/upload ratio for most ISP's calculate the latency due to distance alone and then calculate the distance between the client and server?
With this power, one could take over the world!
Although this could be used to tell your players about their real upload and download bandwidth. You could also gather stats about your players's network connections this way and make adjustments to your game.
