I think that it differs depending on where you lived and who you interacted with. My grandfather that lived in NY said what fedorthedog is saying, whist my grandmother on the other side lived in Kentucky and said what amym505 is saying.
The same is true today, has anything really changed? Go back 15 to 20 years ago. You heard all the violence in NY while Kentucky had smaller numbers. 20 years ago, I would had been so gullible to open the door to anyone. I left my doors unlocked, stopped to help a stranger (I still stop), and I would have gave the shirt off my back. Although 20 years ago, I did a research paper at that time in college for crime in rural vs urban environments and the crime rate was higher in rural from difference sources (Mainly due to wide open spaces, less police force, unlocked doors, items left outside, etc)
Is mass media and population overgrowth made one more "aware" of surroundings? Is everyones' own self knowledge making them more aware of situations along with curiousity, responsibilities, moral codes, standards of living becoming more advanced as one gets wiser and older?
Take for instance the string of "Liberty Mutual" commercials. If I didn't have great insurance right now, I would switch in a heartbeat to them JUST BECAUSE of the commercial depicting how one person takes the time out to help a stranger and another sees it and does the same.
[youtube:1nejqore]http://www.youtube.com/watch?v=PD0Sz91Fd7U[/youtube:1nejqore]