The biggest mistake made here is the inconsistency. He was invited to do business training yet has no job to go back to.
At least he didn't do anything stupid enough to get banned for ten years.
Next time: Try being nice to the border guard. Let them do their job but at the same time try to engage in some conversation that is of interest to them. Don't try to engage to much. Social engineering goes a lot further than the rule book.
Don't forget border guards know how to use the the internet and read his blog/website/Resume. Which leads to the question, if he wasn't working for upverter anymore, what exactly was he wanting to do in the US.
At least he didn't do anything stupid enough to get banned for ten years.
Next time: Try being nice to the border guard. Let them do their job but at the same time try to engage in some conversation that is of interest to them. Don't try to engage to much. Social engineering goes a lot further than the rule book.
Don't forget border guards know how to use the the internet and read his blog/website/Resume. Which leads to the question, if he wasn't working for upverter anymore, what exactly was he wanting to do in the US.