"You own the spot"

Briefly heard Xander tell Morikawa this. I didn't catch exactly what happened with Morikawa's ball. I think this has something to do with marking the ball while at rest, but when you place ball back over marker then it moves after you've lifted the marker and are over the put, you can estimate the spot because you did everything else in good faith leading up to that moment with no penalty. Is this correct? First time I ever heard one golfer tell another golfer that without one of the officials stepping in.