The USGA has adopted a Local Rule for 2017 Regarding accidental ball movement on the green.
The MGC is adopting this Local Rule.
Below is an infographic and USGA guide for implementing this rule.
NOTE: If it is determined that a player’s ball on the putting green was moved as a result of wind, water or some other natural cause such as the effects of gravity, the ball must be played as it lies from its new location.
Click on the Button below for further clarification on what this rule covers and doesn't cover.