Haha, I think your idea is great, I just think it has unintended profiling consequences and is the sort of thing that justifies police overreach. Even compstat (crime tracking system that largely helped clean up NYC and then other US urban centers) is being intensely scrutinized for its role in driving profiling, harassment, and quota arrests in places that aren't war zones. The police aren't great at understanding how systems like this can be used to make people feel safer rather than feel oppressed.