If you ride your bike on a dirt road and there is a fence - door it does not mean that you enter into a private area. The fence is built there to obstruct sheep entrance in the villages, vineyards, olive groves or pastures that belongs to another shepherd. In these cases, open the door and after you pass close it again.
Most times a fence-door from one side is permanently tied with wires. At the other side there is a wire or a string. Untie the knot open the door and close it the same way.