I disagree. There is a live display and if the cop was in his office, he would be monitoring the displays. While it's not perfect, the cameras are generally monitored at least partially throughout the day.

There has been multiple students busted for smoking herbals in their cars on school grounds thanks to the live monitoring of the cameras.

Yes, the cameras busted the students AFTER they smoked America's most valuable cash crop. But it didn't prevent them from smoking in the first place, as the presence of a live authority figure would have done.