Usually outside the interchange should be alright. But if you
don't feel very safe, then go to other places. As long as you learn
from your mistakes, ppl will sure forgive you. Me too, when I just
started taking pix, take pix at various ints, end up getting flamed
like it is now.
It's best to avoid photography within the interchange compounds.
Just now when i'm searching for "photography within interchanges
Singapore" i came across that link i posted earlier and it has an
incident that everyone should remember.
The survelliance of Yishun MRT by terrorists and the plans to
bomb the MRT station.
London Underground & London bus bombing.
Security is tightened due to such crisis taking place in
public transport. Even if we can all say that Singapore is safe, we
cannot let down our guard. General rule of thumb, avoid
interchange/MRT station shots.