Chesterton’s fence

Kevin Staley-Joyce at the First Things blog quotes a great passage from the great G. K. Chesterton (from The Thing):

In the matter of reforming things, as distinct from deforming them, there is one plain and simple principle; a principle which will probably be called a paradox. There exists in such a case a certain institution or law; let us say for the sake of simplicity, a fence or gate erected
across a road. The more modern type of reformer goes gaily up to itand says, “I don’t see the use of this; let us clear it away.”

To which the more intelligent type of reformer will do well to answer: “If you don’t see the use of it, I certainly won’t let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it.”

This paradox rests on the most elementary common sense. The gate or fence did not grow there. It was not set up by somnambulists who built it in their sleep. It is highly improbable that it was put
there by escaped lunatics who were for some reason loose in the street. Some person had some reason for thinking it would be a good thing for somebody. And until we know what the reason was, we really cannot judge whether the reason was reasonable.

How could you apply this principle? You can see how Mr. Staley-Joyce applied it by clicking the link, but what are some other applications of Chesterton’s fence?