Lexi Thompson was informed that she received a four stroke penalty as she walked off the 12th hole on Sunday at the ANA Inspiration. 

An email was received by LPGA officials from a viewer about a possible rules infraction during the third round. 

http://www.tonyslpgareport.com/2017/04/lexi-thompson-receives-4-stroke-penalty.html

it was completely obscene.  1: At the end of the day if the score cards are signed and accepted, the score should be set. 2:  Should some extra special facts come to life, such as in this case an improper ball marking, maybe assess the two stroke penalty, but should not then double jeopardy and assess 2 more strokes for signing an incorrect score card.  Some reasonableness must apply.  3:  If the people and stewards and officials on the course did not report anything, then case closed.  Third party scrutiny from spy satellites and drones should not be allowed.  4:  The leaders tend to be scrutinized and filmed more than less popular players or players further down in the field and allowing outside scrutiny is not fair because not everybody is scrutinized the same