alt Hacker NewsI have seen fights break out in the subway over people being loud. People playing loud music in public often seem to be the types to be looking for trouble, they want someone to tell them to turn it down, so they can say no and escalate. In a lot of cities this is a big risk.
To this point, there have been at least a few stories of elderly people being beaten on San Francisco public transit for politely asking people to turn their music down.