As I recall, the part of the system that warns the controller if two ac are on a collision track where not operational this terrible night. and because of that two controllers instead of one where on duty
I was wandering if some controllers used this part of the system as a reminder for them selves of when to issue a climb or descent order to ac.
If that is the case it increases the risk of forgetting to take action if the controller is used to act on the "warning."