There was an attack we studied in psychology where a woman was being assulted, 23 (I believe) onlookers did nothing.  Each was interviewed later and stated that there were others present, it wasn’t their responsibility.

In islam, stonings are done by the population as a whole.  No one individual is then responsible for the death of the condemned.

I found this statement from here intriguing: The bleeding crowd is easy to love from afar.  The problem with a friend is you have to let him come close enough to see his warts. The reason we want the state to fix things is so we don’t have to deal with things like warts.  In my scenario, diffusing responsibility through a bureaucracy so the individual doesn’t have to deal with what is unpleasant.  The individual is no longer responsible.  Just as an aside, remember that freedom and responsibility are two sides of the same coin.  Lower the one, and you have lowered the other.