Travellers from Canada could face serious consequences if they don't follow a new rule on board United Airlines.The American airline recently updated its Contract of Carriage, which lists detailed terms and conditions for passengers.If you're travelling with United Airlines, make sure to pack your AirPods or headphones if you plan to listen to music, catch up on your favourite TV show, or simply scroll through social media. According to the Feb. 27 update, passengers must use headphones when listening to audio or video content on a device, and any passenger who doesn't comply could face serious consequences.The airline states that it can "refuse transport on a permanent or temporary basis," and passengers who don't follow these terms can be removed from the aircraft at any point.According to the Contract of Carriage, all passengers are required to follow these rules when purchasing a ticket or flying with United Airlines."By purchasing a ticket or ac...