The security in the airports across USA are quite strict. I flew yesterday from Cleveland, Ohio to Louisville, KY via layover in Charlotte, NC. The security checkpoint is not always fun but it is not too bad. I don't know how the securities does in Australia. Here in the USA, Before you enter the security checkpoint line, you are required to show your identification and boarding pass. When they let you in the line, They make you take your shoes off and put it in a bin along with your carry on baggage to go through the x-ray machine. They also make you walk through the metal detector. If the metal detector beeps, they will put you aside and start using the metal detector hand wand to scan your body. It depends at each airport because some of the time, the line can be really long. Some of the time it isn't.
Also, They will request you to put your checked baggage at a location somewhere nearby the check-in area where they have a huge x-ray machine to scan any bombs, chemicals, etc.
I remember I had a strange experience with the TSA (Transportation Security Administration) at the airport 3 years ago. I was following the procedures as I was told to do so. I took my flip-flops, carry on bag, coins and keys in the bin and walked through the metal detector. For some reason it beeped. So they asked me to step aside and they proceeded to use the hand wand to scan me. They didn't find anything on me and the next thing they did was to ask me to sit down and to lift my feet. They even scanned the bottom of my bare feet. At that moment, I thought it was odd to have my bare feet being scanned by the hand wand. I was thinking, Uhm... my foot is bare and what more could it be to this? However, it dawned on me that it is possible someone could put a pin or something on the sole of the feet (yes it'd be crazy but yeah, one could do it).
Anyhoo, If you're flying to Sydney and landing there at night time, Please do take some pictures because I'd love to see it!