I wonder why no referee has stepped in - it's a pretty blatant rule violation (although - as Mike noted - amateurs who are walking, talking adverts for NIKE are pretty suspicious too and that's also ignored).
Another thing that struck me - watching the coverage - was the commentators discussing how players coped in bad weather. The consensus being that players should slow down and play as slow as possible to let the weather pass. I remember this from St George's a few years ago - every time a band of rain came in the players would take forever getting on rain gear and, by the time they were ready to hit, the storm had moved on and they could take them off again. I don't really have a point here other than bloody hell, professional golf is slow and I don't get why golfs authorities are all okay with it.
I was watching the 1966 US Open on youtube (
https://youtu.be/xrxcRtvVA58). Arnold Palmer has a three foot putt at the 18th - probably the most nerve shredding one in his career. He's just blown a seven shot lead and this downhiller is to get into a playoff the next day. It's notable that he didn't mark the ball, he just looked at it and putted. From the ball coming to rest until he hit his putt was under a minute. Given all the problems we seem to have with marking the ball these days why not have a rule on it?
Something like: You get to mark the ball when you first get on the green but - after you hit a putt - you have to putt continuously until you have completed the hole. It'd shave about 20 minutes off a round at the top level. I think they used similar (you only mark your ball once per green) in the 1967 US Open to avoid rounds taking more than 4 hours *bursts into manic laughter*