It was interesting that reading that abstract, that it didn't cite another possible reason - more regular medical examination. I wouldn't be surprised in such a job, flight attendants might be expected to do regular medicals or have other reasons like needing prescription drugs say for sleep tablets. Having more eyes looking may pop up more incidents.
i'm guilty of the kind of avoidance that negates this. For example, you can't be forced to quarantine if you never get tested for COVID. I wonder if there's an official term for this state of mind, it's a tough habit to break and your life could depend on getting passed it.
