We have a full enrollment form that requires all contact information. Our Minecraft systems log every single thing typed by every single player, whether it is sent as a private or public communication. Our administrators in game have full visibility to all private and public messages. We also have a chat filter that blocks a long list of poor word choices from ever reaching the screen. The filter notifies us immediately of what was typed and who tried to say it so that we may take the appropriate action. We believe we are taking every precaution available to us. We remove any player breaking a rule and call the parents for a conference prior to allowing them back in game.
In addition to fully monitoring and filtering the chat, we also log every block that is broke and placed in game. Our admin tools can quickly undo damage and report the student responsible so that we can contact the parents and help them move in a better direction on our servers.
It is our belief that if parents are properly preparing their students with internet safety topics, and we are protecting them by tracking and monitoring everything that is associated with communication on our servers, that this is a safe environment.