Although I do generally agree with those who do not listen to music while they turn, I'll state my belief there are those who do what they do, because that's what they want to do.......and, then there are those who do what they do, because that's what others think they should be doing. Concentration is a state of mind.......but ah yes, there should be rules, but only those self imposed, as a result of knowing thyself!
I used to work in a manufacturing environment, where many of the workers listened to radio, audio books, and played music. There was one woman who listened to the audio versions of her favorite soap box TV programs! There was an R&D guy who complained about all this. He said the practice meant a loss of concentration was the inevitable result. The CEO made the use of personal audio devices ok by company policy.....smart guy! Much of the work there, as well as much of the work I perform making my bowls, is repetitious and boring. For me, I find that bowl making only gets really interesting in the last stages of production.....plenty of boredom! Anyway, the R&D guy eventually got his own radio at his work station!
Now.....I suppose I must state that if I were a lathe turning instructor, I'd advise against listening to any music while learning basic skills. I didn't listen to the radio in my own shop for about the first twenty five years......and, it was about twenty years ago when I first got myself a radio. I believe not having a radio is a very realistic safety issue for beginners.....but, at some point, it becomes a personal choice that isn't going to be a safety issue, if done with suitability to any individual.
Listening to music will definitely be a safety issue when the volume is very loud. Just where that "tipping point" will be, is a matter for the individual. There are those who believe that any audio input at all, is too much.....and, those who don't. For me, listening to music, or the radio is a choice.....and, there are times when I use my ability to make that choice!
-----odie-----