As I said in another post. Its mostly a matter of common courtesy. This is the only game I can think of off the top of my head where you're actions (especially in pents) are likely to cause someone to die. Or die again. It really is hard for me to fathom how it was easier to get a GR with 70+ people on than with 5 to 10. Even if the grave is untouchable, a wave of new NPCs still slows down the process of getting to it. And as is the case with this particular incident, two slightly undersized people trying to inch their way over to the grave are likely to get killed if 3 full pents spawn next to them instead of 1-2 random ones.