There's plenty of professions a con can claim without this problem: an uber/taxi driver, hotel receptionist, child tutor, retail worker, farmers market vendor, stay at home parent, a convenience store, valet, or gas station attendant, a mall cop or bouncer at a bar...
This is classic security theater. Inconveniencing legitimate people while leaving gaping holes for any actual crook to exploit.
In politics and bureaucracies, orchestrating a perception is more important than instrumenting a reality.
Yes, but then that helps down in narrowing down the focus in border control. If you are arriving in US and declare "I plan to work as a taxi driver" or "I'm coming as a hotel receptionist", but you lack the appropriate work permit, it's a flag.
That's not what this is. First, this guy is in the US on a layover between Europe and Australia [1]. And second, these questions are being asked of tourists.
And before you say things are not affordable to people in those professions, flights are under $200 right now. A person of modest means could feasibly save up for an overseas vacation.
My theory is they have KPIs to hit and found denying entry based on challenging field-related puzzles is a decent way to do it. An indicator of how many actual thwarted espionage or terror events is likely harder to quantify (and for most, it's probably zero).
This is classic security theater. Inconveniencing legitimate people while leaving gaping holes for any actual crook to exploit.
In politics and bureaucracies, orchestrating a perception is more important than instrumenting a reality.