Hmm... I believe that the server doesn't do anything with the account in terms of logging in OD.
Mess around with the command dscl in terminal. (read the man page first) It behaves and stores data much like a basic file system.
The reason I think this is that I've set the number in WGM that deletes the users account as soon after a successful sync to 0. The user folder on the client is deleted immediately after logout. The user account on the server stays put and is still there today.
With all this in mind, I have a hunch that if you set this number to something, it sets the client to delete the account from the local directory on the client.
Anyone else have experience with this?