Colonists on Mars will live under special circumstances, possibly causing psychological problems. This page is meant to develop preventive concepts to make the colony safe against catastrophic risks as a result of human failures.
Children are unpredictable. They might open a door that should not be opened. Each colonists could carry a personal key indicating that colonist's level of authority. A child's key would not open doors that are dangerous to open at the wrong time and would not open or close valves or switches that are dangerous to operate at the wrong time.
There might be the risk of somebody running amok, endangering the whole colony. There are many vital system that might be attacked. This risk and the implications can be mitigated by some precautions.
Periodic testing and group training can help to diagnose and counteract psychological illnesses early. Those for whom a psychological problem is detected can carry a key (see children above) which will not allow them to make choices for which it is known that they are not psychologically fit. However, psychological testing is not error free.