better rules experts here than me, but in the case of a ball that is hanging over a lip or may roll back in, I doubt a competitor can "give you" the putt as a way to prevent you from giving it time to roll in. My guess is if they conceded it, and then it fell in, it would have been a 3.
If he didn't address the ball, then the ball moving I don't think is because of him....also at that point it had been conceded so it doesn't matter if it moved.