A player that plays multiple chars at the same time is still only one player. And this server is already the biggest server to this mod, so does it matter if there are ten characters more ingame than usual? Artificial increase of the player count, and the risk of abusing it is too high. Suddenly, a player that would take 10 runs to make the money he needs would only take 5 or less runs, what would decrease the chances of encounters.
