Nothing new there. I havr been held at borders all of the world for hours if not days deoensing on the country. Even the usa, specifically attending a co ference as a speaker, they were trying to determine if i was entering the usa to gain employment.  What is the issue, my anecsote is as valid as theirs!  Besides regardless od what we all think, it is the us border agency's right to question you and if you are not a citizen deny you entry; If you feel hard done by appeal- there is actually a process. But sitting in Canada and complaining about what-ifs just sounds like enititement and hyperbole to me.