I'm not completely cynical about the general public. I firmly believe that most people are good trustworthy people who are kept in line by their own sense of what is right and wrong, not the law. However I am aware that there is a small fraction of the general public that makes a living scamming the largely innocent and trusting general public.

If I hear about somebody's house burning down on the local news, I might chip in a few dollars so that they can get their kids new clothes or whatever. I hear the same story, on reddit, 4chan, HN, whatever, from the alleged victim, and they are coming to me with this story and a collection jar? I'm sorry, I am going to require at least some local news confirmation, and it seems like even that isn't good enough with some of these scams.

And don't even get me started on how in most of these cases the jump from "here is my sob story" to "and that is why I need money" is completely missing. The connection there is clear when a house burns down, but "I threw something out, then later learned it was worth a lot"? "I am a server who was insulted/was not tipped"? Uhuh. If I see a donation cup, and no connection between "sob story"->"now I need lots of money", I don't think that there is any rational conclusion besides "it's a scam".