“I wasn’t expecting what happened today,” Thompson said afterward as tears rolled down her face.
“But I’ll learn from it,’’ she added.
The long-hitting Thompson was told about the penalty as she made her way to the 13th tee after a bogey at 12 had whittled her lead. An L.P.G.A. rules official walked alongside her and explained the four-stroke penalty: two strokes for improperly replacing her ball on the second-to-last green of her third round, which meant she had then played the ball from the wrong spot, and two more for signing an incorrect scorecard.
A television viewer had contacted tournament officials as the final round was underway to bring attention to…