Why would an outsider have a difficult time believing that Cole was beginning his first year of banishment in Chapter 20?

If an outsider saw Cole, Garvey, and Edwin descending the hill that morning, they would have seen three friends laughing and enjoying each other's company, rather than a young man facing banishment.

They hiked back to camp laughing and joking as if they were old friends. Nobody ever would have guessed that this morning marked the beginning of Cole’s year long banishment.