Golf Ethics Question?

Here is a golf ethics question for you.

What if you were playing in the club championship tournament finals and the match was halved at the end of 17 holes. You had the honor and hit your ball a modest two hundred fifty yards to the middle of the fairway, leaving a simple six iron to the pin. Your opponent then hits his ball, lofting it deep into the woods to the right of the fairway. Being the golfing gentleman that you are, you help your opponent look for his ball. Just before the permitted five minute search period ends, your opponent says: “Go ahead and hit your second shot and if I don’t find it in time, I’ll concede the match.”

You hit your ball, landing it on the green, stopping about ten feet from the pin. About the time your ball comes to rest, you hear your opponent exclaim from deep in the woods: “I found it!”. The second sound you hear is a click, the sound of a club striking a ball and the ball comes sailing out of the woods and lands on the green, stopping no more than six inches from the hole.

Now here is the ethical dilemma:

Do you pull the cheating bastard’s ball out of your pocket and confront him with it or do you keep your mouth shut.