After reading this thread, I started to observe the behaviours of shoppers in various shopping centres, ie. VIVO, Centrepoint, etc. (since I must educate myself)
It appears that there is no such practice to keep to your left while on escalator.
I think the reason being that the width of escalator in shopping centres are narrower and shoppers are in leisure mood.
During my observation, I didnt see anyone squeezing thru or rushing up or down the escalator.
When people dont have the habit or the practice of "keep to your left" in shopping centres, it is hard to expect ALL people to change their habit and to do so when they are in MRT stations.
So, I think we should be more accomodating, be patient and should not expect that ALL adhere to the "ruling".

Anyway, I dont think there is much time to save by rushing up/down the escalator. In fact, the act may endanger other users and pose the risk of knocking someone down the escalator.
Dont be too

when others standing on the right.
Be happy,

patgoh
p/s : the above emoticons and many cute ones are available
here. Feel free to copy and use it here if you like them.