I think you are a little nuts if you think PvP players, even in tribes, are going to spend all of their game time protecting non-pvp players so they can go do their business outside of their tribal area. Not only will there almost always be a shortage of people wanting to do that job, but the ones who do likely won't do it for long because it will be boring most of the time. As I said in the OP, policing areas will be a huge responsibility that will feel like a second job.
I did like the idea someone had of crafters being able to set traps, at least ones that might let them have a shot at fleeing.
Look you don't have to agree with me, and maybe the griefer problem is being exaggerated currently, but what you and I agree on is irrelevent. If the game isn't fun for PvE and community players such as crafters, they will leave, and those remaining can PvP each other until your eyes bleed. If the PvE and community player leave, this game will die.
I hope there really isn't a problem, but we might as well start looking at it now to see if we can suggest some solutions. As an indie game, Xsyon already has the cards stacked against it. I understand the romantic notion of a completely open sandbox game, but that isn't even what PvPers want. If they did, they would be ok with crafters being able to do combat too.
In Real Life, I am a Wing Chun practitioner who is an IT Pro and computer programmer. I also build cars and 4x4's for fun, as well as read books about trippy subjects and I like to target shoot with guns. If we want to have an open game here, then perhaps crafters, given enough time, should be able to do full combat as well.