The Most Dangerous Cities

I heard part of a debate the other day about the ranking of the most dangerous cities. One speaker defended the rankings as providing some information.

A second speaker suggested that risks of criminal behavior and of being the target of a crime reside more in the person than in the city. Young men are more likely to be involved in crimes than older women; people who are involved in night life more likely than those who stay at home; those who live in middle class suburbs tend to be quite safe. Thus, he suggested, high crime rates are just an artifact of the characteristics of the population. Cities with lots of high risk citizens have high rates, but a person whose characteristics suggest low risk will have low risk no matter where he/she lives. It seems to me that there is a lot of truth in that position.

I wonder however whether there are not nonlinearities. Can an urban area inhabited by lots of high risk individuals add to the risk of all those individuals? Is a suburb occupied entirely by low risk individuals and families likely to be managed in such a way that their risks are all lower? It seems to me that that too is quite likely.