Following directly from the First Principle: You should assume that someone who asks you to turn your cell phone (or audio player) down or off is in good faith, and you should comply in good faith. They have a reason for asking, and it's probably not that they're trying to dominate you or hassle you or restrict your God-given right to free expression. (For example, people with temporal lobe epilepsy may find that certain sounds trigger seizures, and some people have neurosensory issues that cause extraneous noise to be a severe difficulty rather than a mild annoyance.)