This is NOT a 'murica story. If you look elsewhere in the thread, there are links to this sort of thing happening around the world.
It is a "bystander intervention" and "diffusion of responsibility" human-psychology problem. Both of those are Googleable terms and both have practical solutions in how to bypass them; unfortunately, typically only people who've taken some Psych coursework are aware of them.
Compounding this is the fact that there are MANY crazy homeless people in San Francisco, so you tend to automatically filter unusual behavior out.
It is a "bystander intervention" and "diffusion of responsibility" human-psychology problem. Both of those are Googleable terms and both have practical solutions in how to bypass them; unfortunately, typically only people who've taken some Psych coursework are aware of them.
Compounding this is the fact that there are MANY crazy homeless people in San Francisco, so you tend to automatically filter unusual behavior out.