Segregating passengers

[Cyrano]

Originally Posted by Rwy in Sight

Why is it necessary to segragate passengers at an airport?

Thanks in advance.

Rwy in Sight

If you mean segregating arriving and departing passengers, I think there are two reasons:

• Security: if you let the passengers mingle, then your departing flights are theoretically only as secure as the least-secure airport from which passengers have arrived at your airport;
• Immigration: (the 100-series gates in Dublin are one example, and there are doubtless others in other airports): if passengers with different immigration status can mingle, there is scope for immigration fraud (e.g. swapping boarding passes, or connecting from an international to a domestic flight without having gone through immigration).