We used to "lock" the gate to the back side of our farm with a chain similar to this one with huge old rusty lock clasped through the links. It was a popular place for keg parties and parking and such but folks would abuse the area and we had to add a level of security. Anyone driving up to the gate would see the lock and leave. The chain wrapped around the big locust post and one link was nailed to the the post and the opposite end hung on a hook and could easily be removed by reaching through the gate.

Kind of reminds me of security theater. We were ahead of our time.