actually, it wont get rid of it, but it will make it less likely. If people have to pay more attention to surviving zombies, they will less likely try to murder everyone they see. Yes, there will be little kids who constantly try to kos everyone they see because they think 4.0 will be pvp based instead, but its more likely that they will get bored before they even manage to get the stuff needed to kill someone else. Or when they try to punch someone to death they die because the other person might have a slightly better weapon, or knows the games control. Yes, makingt he game harder wont prevent it, but it will make it less likely to happen.
.
Edit, molt already said what I said, basically XD
.
edit 2. I now understand what you meant, and I guess that could work, making certain areas like say, a military base or a hospital a place where people can pvp would be interesting, cause then it would make sense, because survivors would fight over the right to loot places like those.