What if somebody tries to ruin the experience for others?
It is very rare that one or more participants would try to spoil the experience for others. In the real world of politics, individuals who are absurd or destructive receive harsh criticism from the press and from their colleagues. These are natural consequences, and natural consequences are always the best mechanisms for bringing stability to a social situation. In the event that a participant attempts to trivialize the simulation experience, then, use natural consequences to modify the behavior. It works every time.