Personally I don't think a countries EU/EEA membership is an issue here. Switzerland has signed and implemented the Shengen agreement. This is the only treaty which is relevant where the movement of people within Europe is concerned. Flights to and from other Shengen countries are treated as domestic trips for immigration purposes. AMS has seperate Shengen and non Shengen areas. You have to pass through immigration to get from one area to the other but arriving and departing passenges are still allowed to mix freely within them. Further afield, SIN also allows arriving/departing pax to mix freely without any problems.
As long as passengers have to pass through immigration to leave an airport or go through security to board another flight I can't think of any logical reason why they shouldn't be allowed to mix. Maybe the answer is as simple as crowd managment? Or maybe it's a security consideration (I would consider this to be illogical, but then lots of security considerations/procedures are...).
Did anyone transit through DUB pre 2008ish? Apparently they used to allow arriving and departing passengers mix freely but then they felt the need to spend a considerable amount of time and money seperating them. The answer to this question might lie in the reasons given for these works.
Last edited by Anansis; 26th Jul 2010 at 23:22.