Originally Posted by
zkzkz
Can you name any airport outside the uk which doesn't allow exiting the international departures area via immigration? It's an odd idea, people miss or cancel flights all the time.
I expect that every airport will have a mechanism for doing this, for the reason you mention. But that's not what's being discussed here. The question is whether passengers can easily find a way to land themselves without official assistance/escort.
No doubt there will be a spectrum of different approaches in different places. I can give you one example of one of my regular airports where there have been recent reports here of a system (and therefore difficulties) akin to those at T5: HKG. What I was interested in was your assertion that easy self-landing is universally found everywhere else in the world.