Played a round the other day with a guy, "maybe mid 20's" that right from the first tee had one earbud in and was listening to music the whole round. There were 4 of us in that group and he never knew anyone one of us. I didn't mind, and it seemed like the other 2some in our group didnt seem to mind either. I just played my game and enjoyed the company, and he never ignored any of us or anything. Acually I have thought about doing the same thing a few times. Would you care if someone did that that when the walked up to the first tee to play in your group?