The only "issue" that many teachers have run into over the years is multis or the appearance of multis. Your student are welcome to play, and it's great that you want to use the game to teach, but your students absolutely must not log in on the same IP and then send aid or declare war on each other. Whether they are actually controlled by 26 people or 1, it all looks like 1 person. I'm straying a bit outside my mod zone (forums, not game) but this is the general advice. For specific guidance, speak to a Game Mod and/or admin. @Mithrandir is a game mod.