Lets say somebody wants to have the protection of a village, without living in the village itself. It should be possible for people to swear a lesser kind of fealty to a village, without being a member who can actively manipulate what is in the villages sphere of influence. The benefit would be that their claim would display the village name after their own name. For example,
This claim is owned by Treebeard, (Vassal of Caketown)
The potential thief who bumps up against this claim might well think twice about robbing treebeard, knowing that there likely exists some kind of agreement between Treebeard and the strong folks at Caketown. It is basically extra information for the possible transgressor to consider. The exact details of whatever this Vassalage entails would be wholly up to the parties involved.
A lawspeaker goes to the claim in question, and interacts with it using a 'make vassal' command, in the presence of the owner. Once the owner assents, the tag is attached.
It should also be possible for a village lawspeaker to see a list of vassals by interacting with the village totem, and to remove said vassalage from the list. The vassal should also be able to end the relationship at will.