Banishment is a problem because people could get sick, get mauled, or maybe even go insane because they've been alone for however long their banishment was.

Circle Justice: Is a form of justice but instead of jail you go through things with the victim unless its banishment and if it has changed you then your free but if it hasn't then you must go to jail.

Banishment: To expel from your home to a different country or state. [Verb]

In the circle of justice case of Adrian Guthrie and Simon Roberts they were sent to separate islands(for beating up an innocent pizza deliver guy). They thought this was a good idea but they were sorely mistaken. They just snuck out at night to stay the night the night at relatives and stole supplies from town. They ended up getting the same jail sentence as they originally would of had. So in this instance circle of justice was ineffective and taught them nothing.