In-game assassination is fine and accepted. Out of game assassination obviously isn't, which is what these frauds do. They don't get caught because it's kept hidden from a good majority of the community. Think of it like the Deep Web (watch as I get arrested for just mentioning that). In a world where the Sweepers are basically the mafia both in-game and out of the game, it's not impossible for someone to go out of their way to kill a Player in real life.