In some MMOs, the idea of players being able to engage in PvP combat outside of designated areas can be horrifying. Someone gaining the ability to engage in combat where they shouldn’t could go on a rampage and make use of the full loot systems in games like RuneScape, and make the lives of many players miserable before they are eventually banned. In MMOs like World of Warcraft, the threat is slightly less present. Death is little more than a time setback, the penalty paid in a moderate fee to repair armor.
And speaking of World of Warcraft, everyone is dying. In the streets, in the houses, but mostly in the main cities. For several hours yesterday, on multiple servers, a kill exploit ran rampant through the major cities of Azeroth, with low level characters mowing down players and NPCs without a second thought. The exploit was hotfixed by Blizzard, and the perpetrators have presumably been banned. Eurogamer tracked down the source of the exploit, and found quite an interesting justification for the action:
“We had to. The first account ban for using the kill hack was issued around 30 minutes before we started nuking cities. We did so because we knew it was going to be fixed,”
Now might be a good time to explain that just because you can do something, doesn’t mean you are obligated to.
(Source: Eurogamer)
MMO Fallout 
I think the logic was that if it stayed to people using it to kill raid bosses, Blizz would have denied that it was real and dragged its feet about hotfixing it (maybe even waiting until the next patch.) By putting it in everyone’s face, Blizz was forced to deal with it immediately.