And if you are connecting without a boarding pass for your next flight you CANNOT cross back into the departing area until you get one.

I can't remember if it was BKK or HKG where I was stuck for HOURS b/c the security would not accept the phone boarding pass for the airline I was flying (they only had 2 flights a day and the transit desk was only open a few hours to issue boarding passes AND their partners could not/would not issue bp). A very uncomfortable few hours.

SIN does security checks at the boarding gate which is very different from most - maybe why it consistently gets so many awards - they make it easy and pleasant for the traveler!