Known unknown risks give rise to a myriad of legal questions. The line between those risks and known risks is fluent. They should largely be treated alike, particularly in case of threat to a great many people. In the latter type of cases, compensation of the aggregate losses may be virtually impossible. Caps may be unavoidable. Yet, there should be incentives for those who steer the wheel to act responsibly. Personal and/or criminal liability are suggested as proper means to reach that goal.