Really the only time that this has happened to me this season occurred a couple of months ago down in florida. As a foursome we were walking on a cart course, and let a threesome who were playing incredibly fast (with carts) play through. They were blasting music, but turned it off to hit. The hole is a severe (almost 90 degree) dog leg right and without any practice swings the first two guys step up and bomb it straight down the middle probably ~290. The third guy (a lefty) steps up and wraps this running draw around the corner which catches the ridge that runs through the middle of the fairway, and ends up 70 yards from the hole on a 417 yard par 4. Back in the cart they go, turn the music on, and zoom off to play their next shots. We had already hit our tee shots, and they were playing so quickly that by the time we reached the corner of the whole, the first two guys had already hit (one in the bunker, the other in the middle of the green). The third guy steps up and hits this beautiful half wedge that hits the flag on the fly and drops too two feet. This was one of the hardest holes on the course, and he had basically made a mockery of it. Back on goes the music, and off they go. What I'm trying to say, is that if you can play, you can play music and not get flac from me. These guys blew my mind (and the course was pretty much empty as well, so no one else could have taken offense). On the other hand, if you've never picked up a club and are out on a busy course blasting music, I'll get annoyed very quickly. There's a time and a place, and that is the true distinguising factor that must be analyzed when considering this situation imo.