> very real chance that the mistaken opinion of a border guard would cost you job and your ability to enter the USA for many years.
I'm not sure I understand. If you are granted full legal rights to work, live, and breath in the US by the US border patrol organization (i.e. you have a visa), then there is zero reason a border guard can "mistakenly" not let you in. They can certainly "question" your ability, but that doesn't mean they have any right to immediately deport you without due process. Can you cite a source of this actually happening?
I'm not sure I understand. If you are granted full legal rights to work, live, and breath in the US by the US border patrol organization (i.e. you have a visa), then there is zero reason a border guard can "mistakenly" not let you in. They can certainly "question" your ability, but that doesn't mean they have any right to immediately deport you without due process. Can you cite a source of this actually happening?