We have two situations covered in this edition of Rule of the Week.
Ball is in the fence. You have to look closely, and you will see the vinyl fence has a base. No part of the ball would be touching the golf course if you ran a string/line up from the base. Unfortunately for the player but this ball is Out of Bounds and the player will proceed under Rule 18-2b, unless the Model Local Rule is in place.
In the picture below, the ball is lodged in a fence with no base, therefore, a part of the golf ball would be in bounds. The player could either play the ball as it lies or proceed under Rule 19 for an Unplayable Ball.
Rule 18-2b. What to Do When Your Ball Is Lost or Out of Bounds