Police are for cleaning up crime scenes after the fact and trying to catch the people responsible. There's almost nothing they can do before a crime is committed. Even if a crime is in progress, they're more interested in protecting their own skin than in protecting yours. (Ever notice that a dead cop is a tragedy and a dead civilian is just another day at work?) I've known people who were attacked around the corner from a police van and the police did nothing, if they even bothered to notice at all.
Responding to being robbed isn't an exercise in patriotism.