I was watching some ReveLAtions vids and Daigo was wearing headphones while playing which I'm assuming to block out sound. Haven't seen anybody do that before...
Mike Ross wore headphones during EVO2k10... It teaches to react by looking at the screen instead of hearing the buttons. A lot of players get susceptible to listening to the controllers/sticks, they react on listening to it, and if the other player is smart enough, they will press buttons to get the reaction out and counter it.