A few years ago, a US border official didn't even know about my visa type (O1) and put me through secondary because he didn't know that the visa existed.
This also happened on the US/CA border to me - the official told me I had the wrong visa to which I responded I had the correct visa. We went round 15 times in a row back and forth, with me stating it was the correct visa until he gave up and let me go.
A close friend of mine also had a gun put on the table to intimidate him in a secondary screening when coming from the UK to the US.
So much for wanting to be an "immigration magnet" like the Google hangout tomorrow with the CTO of the US.
http://www.whitehouse.gov/blog/2013/08/21/we-immigrant-geeks...