First time poster, long time lurker. Perhaps there is a solution. The people most at risk of losing it all to the roll of the dice are the lone survivors. No matter how safe you play someday you get sloppy and Boom! If your in a group you at least have certain level of redundancy, someone has your back, or at least a blood bag and a DMR on overwatch. In a real Zombie meltdown at first there would be a certain we're all in it together attitude us v the zombies, as in the game most people would rub along shouting "Friendly" and playing nice. After a while when supplies start to run out (or on DayZ when the pleasures of hunting for tins of beans begins to pale) bandits would realize that there was no one to prevent them from taking what they need be it a LA85 AWS (you know who you are!) or scarce food. At this point all a survivor is is a bandit without a (decent) gun, to the other guy, while you may want to avoid him, he does not want to avoid you.
Perhaps there is the possibility of supra factions. When you would run across a member of your supra faction (perhaps identified by an armband or such) you hold fire, this would allow the possibility for lone survivors to build an adhoc raiding parties. As in real life like minded people would band together for safety. Imagine the feeling of spotting a survivor in the trees, carefully taking aim only to realize he's one of yours, after hours of roaming the wilderness alone and afraid you found a buddy or three.. Of course this would make the life of a bandit more exciting, as word of there activities in an area would spread more faction members would converge to eliminate the theat. Team killing and such would result in you losing your arm band and becoming a bandit and fair game, and never being able to rejoin (which would certainly make people think again) I also think that it would make bandits real bandits, not just player who kill and loot you, but real outcasts from respectable society.... What would be interesting is how multiple factions would rub along, would some have friendly relations, others be sworn enemies? would there be have temporary truces in order to kill common enemies? The game (and its the most interesting one I've played in years) is set up to make it player v player, unless you have a couple of friends to play with, this would make it gang v gang. Anyway fire away!