Not to be antagonistic, but I've seen plenty of this on the social.bioware boards too. Seems with the game being ~10 years old, and a limited player base, players are treated almost as resources (they can be stolen and poached) with the different servers battling out for player base superiority.
Stolen and poached? It sounds like you think that your server owns the players and that they are not allowed to play anywhere else. Perhaps you should let them know that and see what kind of responce you get. Still that is not the case here, It is not like this is the website for any given server, It is a board for NWN in general.
Believe it or not there are even boards decicated to a sole server that allow other servers to be advertised on them. I currently have a DM who has become less active because he has started DMing somewhere else. The server he has moved to is denoted on our boards. The larger crime would be to limit the options of the players from playing where or with who they want. The servers are there for the players enjoyment after all, not the other way around.