I was not personally involved, but I think Mahkra and Avatar pretty much captured the reasoning behind the punishment. I would like to emphasize that I think 95% of these types of incidents can be resolved peacefully if both players keep their cool and talk. I dont understand what would make a person lose their cool and either go off on someone else or take action to disrupt their play without discussion.
Take a minute, ask nicely, and if that doesnt work consider some other action. We need to try a bit harder to get along. In the real world, if things dont go your way, you dont get far by going off on someone, trying to kill them, run them off the road, or whatever. Consider that next time you have "mud rage"
