Thank you. I've been waiting for someone to bring up EQ. They did open raid bosses amazingly well. As an old EQ raid leader I always felt so accomplished when we managed to take down the bosses because it took the coordination of 60-70 people to take down that boss. The EQ raiding system from launch to Planes of Power (that's 5 expansions of raids including release) was all done in an open world setting, and you didn't dare run around and try to grief people's raids because if you died you would have to run back and get your corpse to regain all of your equipment. None of this ghost mode, no-mob kind of business either. Your character came back to life at the nearest city and had to either get a rez, or run back to where you died though all of the enemies.
If open raids could be done well that far back then there is no reason that it can't be done now.