There will be no real PvP system

[MongoJerry]

My brain did not wrap around that too well. If a Griefer kills me three times, I am out or he is out? Or, do I have to mug him with my gang three times and call a GM to dispose of the corpse?

The second case. After an invader dies three times, they are supposed to leave the area for an hour, and the GM's are supposed to forcefully enforce this if the person does not comply voluntarily. This depends on the responsiveness of the GM, so one's mileage will vary greatly, but it is supposed to be an option. The rule was put in primarily to keep mass raids from continuously invading a town, but it does also apply to individuals and small groups.

Your assessment is that the grief PK is, due to being generally antisocial, less likely to cluster, even in small groups.  I assume that the gang mentality translates pretty darned well onto the internet, and that the healthy Killers will be doing as you suggest if the content shows up, and that the "deviants" will find enough kindred spirits to cause hate and discontent.  I cannot predict whether or not Blizz will do as you suggest -- I support your position on that in any case -- and deal with deviants.  I must admit I like what they did to the botters yesterday.

Ah, yes, I was considering the solo griefer. It may sound counterintuitive, but I consider team griefers to be less of a problem. First, teams of griefers are harder to form and they are unlikely to last as long in an area as an individual. Some members of the party will have real life stuff that will make them have to leave and/or some of them will not be as deviant as other people and will get bored faster than others.

But second and more importantly, teams of griefers tend to bring about teams of defenders. Let's take Bolty's experience of one level 60 undead mage running around the lake in Redridge. When level 60's puttering around Ironforge hear about this, the typcial responses are, "Bah, it's not worth it," "It's too far away," and "It'll be a pain chasing that guy around," etc. On occation, a lowbie person adventuring in Redridge in this situation will have a high level friend who helps him or her out, but for the most part, one member of the other faction running around a lowbie area isn't going to illicit much response from high level potential defenders.

However, the situation changes greatly as the size of the enemy party increases. The more people in the enemy party, the more likely those same level 60's in Ironforge are going to think to themselves, "Hey! This could be fun!" The bigger the enemy party, the less time one is going to have to spend running around hunting down the enemy party. (The larger the invading party, the easier it is to find). There are also (obviously) more targets to kill, so it becomes more worth it to travel to whatever location is being invaded. Finally, there's also the social aspect of it, as people on the PvP servers I've found tend to be very social. If the enemy party is large, then it's easier to message some friends and say, "Hey! Raid on Redridge! Let's head down!" In my estimation, a party of one or two invaders will not illicit much response. A party of three or four can be stable for a little bit, but eventually someone will call in some high level friends to help out if the invading party causes too much trouble. An invading party of five or more will bring in high level strangers to help almost immediately.