Originally Posted by
tigertanaka
2) What is the reason behind barring passengers who have taken the right hand door at the entrance to the departure gates (next to the downstairs WH Smith) from re-entering the main terminal area? I can't think it would be due to departing/arriving passengers mixing or any potential security reasons but maybe someone knows better.
The doors are in place to stop arriving domestic passengers going into the airside departure lounge. This also like you mentioned to stop or at least reduce domestic and international passengers from 'mixing' with each other. Also helps arriving passengers know where to go and not accidentally end up where they shouldn't be.