"It seems like the guy was added to some black database somewhere." Or, a much more simple explanation as was outlined in a post above, is that they asked what

"It seems like the guy was added to some black database somewhere." Or, a much more simple explanation as was outlined in a post above, is that they asked what he does for a living, and he mentioned cryptographic technologies. Which is a controlled export in this country. Which would naturally raise the curiousity of someone whose job it is to monitor the flow of humans and properties in and out of this country. Someone who enters and leaves this country frequently, who works in an area that is a defined controlled export of this country... Tell me, if your job was a border agent, would you be curious? Would you interview that person? Wouldn't you be horrible at your job if you didn't?