I am constantly seeing comments regarding the ALT+F4 problem. The way I see it, there is a simple way to fix it. I'm not sure how other MMO's do this but Eve-Online gets round this with an "Aggression Timer". When you are being aggressed by the NPC's, you can log out but if a player takes a shot at you, you either sit there if scrambled or you get off-grid and sit there for the 15 minute aggression timer giving players time to scan out your location and kill you. I would suggest DayZ goes along the same principal. If a player fires a weapon in your vicinity and you ALT+F4 or abort, you should either sit in that EXACT same spot for 30 seconds or your character disappears but sits in a Zed-free area for roughly 15 minutes within say 0.5 km from your log-off spot. If the ALT+F4'er logs back in, He goes back to the original place he logged out at making it easy for you to keep a guy there watching while you scout out his log-off location.