"American thing?" I'd say we have a level of fear here that comes, among other things, from watching way too much TV news. We're also (biologically?) programmed to be wary of anyone we perceive as "other."
When I was much younger and living in Boston, I was getting ready to leave the parking lot of a 7-11 when I was approached by a white-haired, frail old woman. I had a wee adrenaline rush and thought about rolling up my window. My next thought was "Darlin', you've been living in the city too long."
She asked me for a ride back to her seniors' apartment building, because she was having heart palpitations.
