And Phil Mickelson took action against the creeping intruders.
On Friday, Mickelson — who's been hovering at the bottom of the leaderboard himself — decided to have some fun with a ground camera. Walking down the fairway, he chased after one and gave it a friendly kick.
We know the Chambers Bay course is torturous — but bringing in a Mars rover?Lefty's out here kicking drones. pic.twitter.com/BYeS6qX0t8— Robby Kalland (@RKalland) June 20, 2015
Check out @FOXSports rolling drone on the 9th green at #ChambersBay #USOpen Also seeing flying drones as well today. pic.twitter.com/rY7tUUGsAV— Play Chambers Bay (@playchambersbay) June 16, 2015