Originally Posted by
Globaliser
That just goes back to first principles everywhere: If you have arrived from another country, you must be re-screened to local standards before you depart on another flight.
Situations where you don't get re-screened are exceptions to the basic principle.
If you have to clear immigration, then by definition you have arrived from another country, thus triggering the basic principle.
No, this isn't true at all. Even in some of the countries you listed if you don't have to deal with customs you don't have to clear security. For example in Canada if you're transfering to an international flight you can go directly through immigration and be airside again (and it's a fast immigration check too, the whole thing takes seconds).
At CPH arriving from NRT I cleared immigration just to get to the lounge and then back through immigration to get to my UK flight. Never had to go through security.