Originally Posted by
SQTraveller
Interesting. I did it the other way round. Went from T4 (travelling CX) and wanted to meet a friend in T2 before they flew off. They checked my boarding pass and let me go onto the shuttle bus.
Now, while I don't know the exact circumstances that you were rejected from the opposite direction, but I wonder if it was because a) they only allow it one direction (T4 > T2), b) you didn't have enough time to get back. If I recall correctly, they only allow you to change terminals if you have 2 hours on your boarding pass (or maybe it was 1hr and a half).
non T4 passengers are not allowed to go to T4.
there has been cases / reports of T4 passengers going to other terminals