One of the issues I see with the security is the fancy system they have for pushing the trays out into the scanner, which is different from pretty much any other airport I've ever flown through. It constantly flummoxes people who aren't used to it and you can see why. Most other airports - you grab 2-3 trays, your sort your belongs, all of your items go through as a group. At T5, you've got to push your first tray onto the main belt, grab your second tray, wait your turn until there is a break to push forward your second tray. I've seen people with multiple trays stacked up, waiting to get them all on to the main belt at once. And of course there are always the people trying to jump the queue and get their tray onto the main belt before it's their turn. Seems to create additional stress and confusion for little benefit.