I do sort of wonder what effect, say...20 hours of travel has on 'cognitive overload.' Personally, I've occasionally had trouble following and answering the lines of questioning by IO's. It wasn't that I had anything at all to hide, it's that I was flipping exhausted and fuzzy-brained!
And what about things like language barrier?
When you consider the number of other factors that could complicate the immigration entry interview (or, indeed, any other law enforcement situation), then, from another perspective, the article could be seen as 'how to turn innocent, honest people into criminals in 5 easy steps.'