My first thought is that sooner or later the police will stop responding assuming it is fake, and then when a shooter really shows up and if someone makes an actual call for help, nobody will respond and the perp gets away.
I have seen sophisticated burglary rings that strike when there is a violent thunderstorm in the wee hours of the morning. A violent thunderstorm will trigger burglar alarms, and police know it. They are disinclined to get soaking wet checking out business burglar alarms during a thunderstorm, because they know full well that your average thief is not out in the rain.