There's a hint in some of the reports that the Chinese passengers were well aware they couldn't transit, but thought that if they got past airline check-in -- somehow -- then HK authorities wouldn't stand on formalities and would let them return to the Mainland. Maybe Mainland authorities would have been flexible in a similar situation, but HK authorities aren't. So the passengers sort of went on strike and just sat in the airport for days, refusing to fly back on EK as they were instructed. Now they're in HK quarantine for two weeks. Interesting to see where they'll be sent when that's finished.