On Saturday at the Hero World Challenge, Collin Morikawa was assessed a two-stroke penalty on the fourth hole for a breach of Model Local Rule G-11, which restricts the use of green-reading materials.
According to reports on the ground, Morikawa's caddie used a device (a level) on the practice green to calculate slope which is not illegal, but he then added that info to his handwritten notes in the yardage book which is a breach of the rules.
