Isn't it true? "Oakland is fine, just don't go to [bad neighborhood in Oakland]" is just a more localized form of "The Bay Area is safe, just don't go to Oakland" (a premise that most people here seem to accept).
"PA is safe, just don't go to Philly", "Philly is safe, just don't go to North Philly", "North Philly is safe, just don't leave Temple's campus"... etc. It's all just a matter of scale. You could break it down by block if you wanted to.
Well, at some point you're down to the addresses of known murderers, at which point I don't think you'd want to sub-divide any further. "Franky's house is fine, just don't go in the basement".
"PA is safe, just don't go to Philly", "Philly is safe, just don't go to North Philly", "North Philly is safe, just don't leave Temple's campus"... etc. It's all just a matter of scale. You could break it down by block if you wanted to.