My sanctum door has an enchantment on it. No one can even find the door unless I make it visible to them. That being said, I only keep people out to protect the enchanted artifacts inside. Anyone can enter if they just ask permission first.
But to answer your question, honestly, there's nothing stopping them from doing it again. Laws don't exist here because everyone comes from different realities. What's illegal or 'wrong' in your reality or mine may not be the case in someone else's.
As for a solution, I don't see why there has to be violent repercussions. Perhaps figure out a way to lock down whatever computer runs your training scenarios? If that's what could potentially hurt people and not the room itself, I'd say start there.