Airport Express service is subject to sudden change, especially skipping Kowloon Station. Just this past Sunday, for example, the Airport Express skipped Kowloon Station and Tsing Yi after 1pm.
Let's also add that when there are adjustments, the MTR does not usually post signs. Instead, they make announcements in Chinese and English throughout all the stations. However, the acoustics of the stations are so bad, the announcements are practically unintelligible.
EDIT: Right on schedule as if to prove the point, the MTR has announced that tomorrow, Thursday, the Airport Express will run only between Hong Kong Station and the Airport starting from 1pm. And no check-in service at Kowloon Station all day tomorrow. (This is not posted on the MTR site but on Mingbao.)
Last edited by 889; Oct 23, 2019 at 8:46 am