The first time, I usually wave and give a thumbs up for a 'good shot'. IF it happens again, I say something about being safe on the course. Maybe they don't know and playing their best round. Who knows.
I just got this on a trade. It is 10.5 degrees with a Hzrdous 70 gram shaft and love it. I have gained some yardage with it! Looks great with the rest of my Taylormade clubs!