I've been playing and watching golf for over 50 years and have never seen an incident like the one that happened yesterday at the PGA Championship. Bottom line: it's up to the player and his caddie to make sure they are following the strict rules promulgated by the PGA and USGA.
Having said that, I can't imagine a more confusing scenario for a golfer who is in thick of contention on the last hole. No way did that look like a sand trap. And if it was, why were spectators actually standing and yes, SITTING in the sand trap? If the officials had done their job, they would have told Johnson to wait until they cleared the spectators out of the hazard before he hit. That was a mob reminiscent of the hordes of spectators that used to charge up the fairway after the last shot on the last hole of the British Open.
I would be ashamed if I were the PGA in the way they: 1. allowed that area of the course to get so trampled 2. were no-shows on the most important shot of the tournament and 3. embarrassed the golfer while he was still on the green. Why did they not wait until he was in the scorers tent to confront him since they hadn't done their own job back on the course?
Tradition and integrity are important. But just once I would like to see the PGA come out like the other major sports and say "our officials blew this one". Apparently this is one sport where some people are perfect.