On September 14th, 2017, during the Albertsons Boise Open, Ben Crane completed his first hole. He found out he had training dots on the face of his driver. These dots are used by a launch monitor.
He called a Rules Official to tell him he carried an illegal club and did not play with it yet. The penalty in 2 strokes per holes the illegal club is carried maximum 4 strokes per round. He declared his driver OUT OF PLAY. The Rules says that if the breach is between hole #1 and #2, the 2 stroke penalty is also put on the next hole. Crane made a 4+2 on the first hole. After the play of the second hole his other par became another 6.
After 4 more holes, Crane remembered he had those dots also on his 6 iron. He gave that information to the rules official and had to add 2 other strokes on his first hole and 2 more strokes to the score of his second hole. his first two holes were 8-8.
NOTE: If he had made a stroke with one of those clubs, he would have been disqualified right away.
In the evening, the rules official discussed the matter (probably around a cold beer) and decided that the breach was more important than previously thought. They consulted USGA. Because Crane did not declare the 6 iron OUT OF PLAY immediately after the discovery of the illegal driver, he had to be disqualified. He should have known that he had another illegal club.
COMMENTS: This penalty is not due to the lack of the knowledge of the Rules of Golf but his own negligence, in the same fashion as starting a round with more than 14 clubs.