I read the Philadelphia Reddit board sometimes and half the posts (exaggeration) are things like "I'm driving in this weekend and where can I find parking and not get killed" or "is X neighborhood safe???"
And, frankly, it isn't the "sketchy" (poor, minority) neighborhoods where visitors should worry about the kinds of crime they worry about. Muggers don't waste their time in poor neighborhoods because they're, you know, poor.
Poor neighborhoods do tend to have more violent crime, but it's a different kind of crime.