Quote Originally Posted by Lethallin View Post
Their syching with the client really isn't very good.

For the most part, the server believes the client if the client says it's in position X,Y,Z. There's a few checks for client modifications, but it's not very great.
The reason behind why MMORPGs tend to trust the client when it comes to movement is simple. It takes a lot of CPU power to track the movement of hundreds to thousands of players in a 3D environment. It's trading security for reliability and convenience.