Re: lights
If it is glowing at irrelevant times, it is either due to human error (if the lights are turned on and off by operators in the control room) or due to flaw in the automatic control circuit (again an indirect human error!)
If the lights are controlled automatically, the circuit may contain a timer (possibly a Real-Time Clock), light sensor circuitry (possible a circuit using LDR), set of relays and driver circuits to turn on the relay and a microcontroller programmed to control all these operations.
In this case, if the light glows at irrelevant times, it is due to the programmer who coded the microcontroller.