REGARDLESS of how the mystery surrounding Malaysia Airlines Flight MH370 ends, it has already left a mark on global aviation security.
Security experts in the United States - a country which put in place some of the most stringent airport checks after the Sept 11 attacks in 2001 - say that airports all around the world will now likely review how they process passports to ferret out bogus ones.
"I think the fact that two people were able to board this airplane with stolen passports - even if they have nothing to do with the crashed airplane - underscores a vulnerability," said Mr Brian Michael Jenkins, a former member of then President Bill Clinton's White House Commission on Aviation Safety and Security who is now senior adviser to the president of the policy think- tank Rand corporation.
"Governments are going to be reviewing those procedures to ensure that people are boarding flights with a valid passport."
And if terrorism turns out to be a key factor in the MH370 incident, there may well be a halt to the recent shift towards screening passengers based on risk from a one-size-fits-all approach. For passengers, that might mean recent changes to improve convenience for frequent fliers - like an express airport security lane - are rolled back.
The presence on board the missing plane of two passengers travelling on stolen passports has been a key source of speculation about foul play on the flight.
The US Federal Bureau of Investigation is now checking the fingerprints of the two passengers provided by the Malaysians against its database of criminals.
Recent Interpol reports, however, suggest that passengers travelling on stolen passports are not entirely uncommon.
The global police agency estimates that last year, over one billion passengers got on flights without having their passports screened against its database of more than 40 million stolen or lost travel documents. Of the passengers that were screened, some 60,000 were found to have been using stolen passports.
Experts say, though, that tightening controls may be more complex than just making all immigration agents query the database.
"Checking every single passenger against a list of millions of stolen passports, just the sheer volume of it, inevitably there are going to be errors. If you are going to check, then you have to have a way of resolving the discrepancy. That's going to slow things down, people are going to miss flights and it will cause irritation," said Mr Jenkins.
If anything, countries have been moving towards loosening immigration controls rather than tightening them. This is in part a response to passengers' increasing impatience over intrusive procedures and also a move by airports to focus resources on passengers deemed to be of the highest risk.
In January, the European Commission started to allow passengers to take on board larger bottles of liquids purchased from duty-free stores outside the European Union, with an eye on completely lifting restrictions in 2016. The ban on large containers of liquids and gels was put in place in 2006 after British authorities uncovered a plot to bomb transatlantic flights with liquid explosives hidden in soft drink bottles.
In the US, the Transportation Security Administration recently launched a Pre-Check programme that allows pre-approved passengers to skip many screening inconveniences like removing shoes or taking a laptop out of a bag.
In December, the Federal Communications Commission said it was going to consider lifting the ban on in-flight mobile phone use. A passenger flying cross- country in the US would have phone signal for much of his journey.
"I think we are seeing a little bit of a disturbing trend," said Mr Jeffrey Price, an airport security coordinator trainer for the American Association of Airport Executives. "We're kind of doing what we always do where the further away we get from tragedy, the more we forget that it happens and the more we forget why we do the things we do."
Mr Price, who also owns aviation management consulting firm Leading Strategies, added that the real impact on security will depend on the precise circumstances surrounding the fate of the Malaysia Airlines jet.
Mr Douglas Laird, a former secret service agent who is now president of aviation security firm Laird and Associates, echoes these sentiments.
"If this aircraft was brought down by a bomb, what was the explosive, were chemicals combined on the airplane to make the explosive or did they come aboard the airliner with the explosive already made," he said.
He said, however, that every airline incident inevitably leads to reviews that seek to stop the same mistake from happening. He recounted, for example, how a presidential commission proposed more stringent screening of checked-in bags after Trans World Airlines flight 800 blew up in 1996, even though the cause was ultimately deemed to be mechanical failure.
"I would hope some good comes out of it and that we decide how to do things better. It might be a better way of screening passengers, it might be a better way of screening luggage, but (what is) more important to me is we need to get a handle on stolen and fraudulent passports."
This story was first published in The Straits Times on March 13, 2014
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