Free shuttle bus from Hong Kong Airport

Yes, you can take free shuttle bus lines from HK station or Kowloon Station by showing the ticket and boarding pass. It is valid for 180 days from the date of issue. So, you can use it on the fourth day. In addition, you can use it the ride on MTR lines (except Airport Express, East Rail Line First Class, Lo Wu and Lok Ma Chau stations) within 72 hours after swiping it for the first time at the entrance. :)