3 days tourist pass in hong kong

What happen if i stay in HK for 4 days but the AE 3dsys tourist pass that I intend to purchase is only allow for use up to 3days unlimited ride so what happen after the 3rd day do I still allow to use it for the MRT ride & for my free airport express train to airport if I but the HK300 AE which come wit free 2 single journey airport to Kowloon.