"Apparently, wait times at exporting countries are leading to contamination exposure. Cars stored outside on grass are vulnerable to insect invasion, and seed contamination creates a biohazard that threatens Australian agriculture. It takes 24 hours working three shifts to unload a vessel carrying 3000 new cars — approximately 125 new cars per hour. But it takes a quarantine cleaning team 10 times as long to thoroughly check the cars — that’s 9 cars per hour. The cleaning teams are currently only working during business hours."
It all makes sense now. Really good read, thanks for the link.