I read in the Qantas forum that there is also a security checkpoint into departures on the arrivals level at the bottom? This is mainly for those who need to claim their luggage and then bag drop it after customs, but is available for anyone and is usually not very busy. Is this true?
That is exactly where we went after reading in QF forum and had scouted it before - apparently it totally depends on what time of the day. When I looked it up the day before after arrival from HKG, that check point was virtually empty in the early afternoon. So I thought great we would use it for our 9am flight tomorrow.
WRONG, Like I said you could not see how long the line was from outside the entrance where you only saw a few people - the actual line inside was looping around at least 4 times if not 5! Because many people have lots of stuff to bring the screening went very slow. Most of them were connecting passengers after getting off their international arrivals and cleared immigration/custom. Every few minutes the TSA personnel sitting right behind the entrance was telling people to walk to their departure terminals would be much quicker. More than a few times he had to look at people's BPs and explained to those how to walk to their terminals as many had not the slightest clue. I almost wanted to walk out but my husband said just to wait it out... Double Wrong as it took almost 30 min before we were thru.
Then when we saw the near empty T4 check point from above, we were kicking ourselves to be too "clever' to try the arrival level check point.
Trust me, the corridor is a life saver to avoid the TBIT nightmare during the flight banks that concentrate at certain periods of the day. Outside those periods that check point is deserted, like the early afternoon the day on our arrival.