Don't quote me on this, but I distinctly remember reading an IATA memo a couple years ago about heightened document security for flights from certain airports (inc. AMS and ICN among others) heading to APIS mandatory countries (inc. USA/Canada/etc...). There used to be a very high rate of document fraud (checking in with one passport and dumping it en route, switching passports in flight, etc...) so this measure was implemented. The alternatives were to retain copies of the front page of all documents at checkin, which is impractical due to delays and checkin automation trends - or to retain electronic document information for a 30-day period (which was somehow in violation of EU privacy rules IIRC).