This kind of thing is often not as obvious as it sounds. I used to work for a company that did a similar trick for ambulances, and it was an amazing amount of w

This kind of thing is often not as obvious as it sounds. I used to work for a company that did a similar trick for ambulances, and it was an amazing amount of work to try to persuade customers that this kind of statistical prediction could be useful. Also, there are often other considerations; depressingly often there's political pressure, for example. One could easily imagine in this case that there might be pressure to show a stronger police presence in low-risk wealthy suburbs over the hot spots that might tend to be poorer.