The idea here is that if say I wear a Darfari war paint I should be able to walk into the summoning place and the npcs don’t aggro unless attacked first. This will open up some RP opportunities like playing a thief and add some tactics to pvp. You can try to escape into a capital city if you change into the appropriate war paint while your attacker might not be able to.
I spy… a nice idea. 
Just seems like a hassle. And abusive if you could walk to the middle of an enemy camp and then start attacking. Realistic, yes. But also gamebreaking.
And to use the Darfari as an example is a bad one. I’ll tell you what I told someone else who suggested being able to befriend NPC factions.
Darfari or not, you are a stranger. They don’t know you. Darfari are cannibals. That makes you a source of dinner, not necessarily an ally.