I think it would be really cool if there was a way to set permissions for your tribal land, either on a person to person basis or as a "friends" sort of thing.

It seems that a valuable commodity is land and what you do with it, so one thing to trade would be permission to do things like scavenge or gather on your tribal land without the message popping up that you're encroaching on other's territory. I also like to trade in resources and it would be awesome if I could allow certain people to place things like bundles of grass or leather or whatever down inside of my tribe where it would then become my property. Would mean I'd have to stop moving a lot of little piles from outside my borders to inside.