I used to work at an airport scanning packages (x-ray) for unsafe or illegal items. However it was the general scanning process that makes me really over pack these days. The amount of items and limited departure window was intense. The packages would be dumped onto a fast conveyer, x rayed and scanned  by inividuals. The items would be then thrown several feet behind them into a cargo pod. Each package had only a few seconds to be grabbed and scan. Failure to do so would become the next in lines responsibility. If everyone missed it simply fly off the end of the belt. Here's where serious damages would occur. If your jug was sitting happily in the pod and the next item was  (surprisingly popular from Amazon) a set of dumbbells you can imagine the force they would land with.