Even when scammed, most of us are rational and will avoid drastic measures.
But there is always the chance that someone that is scammed will strike back.
This is an interesting story that is similar.
Murder by Internet
Chris Marquis was a 17-year-old Vermont hustler running a small-time scam online. His virtual business was going great - until somebody killed him. http://www.wired.com/wired/archive/6.12/murder.html?pg=1&topic=&topic_set=
(The story runs for multiple pages)
Obviously such drastic actions are wrong and people should rely on the legal system and not retribution.