The vigilantes had been banned from the official servers for taking advantage of an item duping bug. Even though they're no longer welcome in the legit M59 community, they're still going out of their way to preserve it. They weren't the only ones banned, either; the admins running the server had also been banned.
Massively asked Near Death Studios co-founder Brian Green about M59's pirate server problem. "I wish people would take that drive and creativity and create new games instead of stealing old ones," he said. "But in general, this does show that some people are very passionate about the game." When asked about the banned players, he said: "Meridian 59 is a PvP-focused game, and cheating harms PvP for everyone."
One of the two vigilantes went by the name Revenant, and had been a well-known (and somewhat reviled) player killer in the Meridian 59 community. He claimed that the bannable offense on his account had not been performed by him, but by someone with whom he had shared the account. He sought reinstation, but was denied. On why the accounts were not reinstated, Green said: "Unfortunately, people do share accounts against the Terms of Service, but the actions of the account are the responsibility of the owners."
According to Green, Near Death Studios was forced to ban about 5% of its user-base as a result of the exploit -- a painful blow, as the game is only marginally in the black.
[Via Raph Koster][EDIT: As a result of a miscommunication, we mistakenly reported that Revenant was one of the vigilantes. In fact, he is one of the operators of the pirate server. We apologize for the error.]