[mc32]

It's possible it might mean fewer long-time residents means fewer people knowing the state and characteristics of a neighborhood and thus fewer people to notice patterns and know what's out of place and not, so fewer people to intervene against anti-social behavior and fewer people calling the cops, so it goes down hill. A tourist might not care about antisocial behavior that does not affect them. Mugging, breaking and entering, theft, etc. Whereas locals would have a stake in the health of their neighborhood and intervene.

[Retric]

Many properties spending significant time empty seems like another huge issue.