Originally Posted by
FedGuard
They don't stop threats, they stop discussions after you find something.

You are confusing two different presentations of the question. Most people in this thread are talking about check-in agents and the dopey, feckless ICTS "security" types as one enters the check-in queue or boarding queue, not when it is asked by customs.
The flags raised and reactions had can sometimes be quite different between the two when asked or answered in the affirmative.