Here's my story...
Arrived at one International airport in Australia and queued for checkin.
A security officer was doing Ion testing of "random" passengers and their baggage. So off they go and start swabbing my backpack and planned-to-be-checked baggage.
Into the machine it goes. Then (in similar fashion to Border Patrol) it makes a little noise and instead of it being green bar at the top, it went red.
Ooops. Apparently traces of explosives have been found on me.
So I get asked a couple of questions about my baggage.
Next step is for them to clean the machine down, and retest me.
I was advised that I would be scanned again twice. If both came up clean, I'm fine, otherwise my baggage would be hand searched.
So off goes sample #2 into the machine.
Green.
And then Security person scrubs all over my bags and puts in sample #3.
Green.
I'm thanked, and allowed to continue.
I'm wondering how much of a search the would have performed, and how much time it would have taken if one of the additional samples went red????