I will come back after the race just to watch the cut off time.
I was at Bali Marathon earlier this year, they started dismantling the finish gate as soon as the Cut Off Time is passed, and runners kept on coming in.
Like what uncle kohpapa mentioned, this no-earphones/music policy only imposed on triathlons and multisport events...won't affect pure running events, unless you're an elite chionging for podium. I was caught by surprise during my maiden triahtlon, mp3 player kena confiscated by race official and can only redeem after race LOL. Love it or hate it, rules are rules.