Earlier quoted context omitted.
This behaviour is so bad on London (above ground) trains, if they ever do 'crack it' and roll out mobile signal to the Underground, those tiny carriages will be unbearable.
There already is signal on many underground lines, and it’s pretty rare that people are playing things out loud in my experience?
It is noticeable on buses and overground when people play things out load, but to be honest quite rare in the grand scheme of things.