My anecdote - I'm Australian, lived in USA for decades, moved to Europe after 9/11. Every time I visit the USA it is an hours-long ordeal to explain, in fine detail, why I have the views I have, why I follow Snowden, why I participate in European hacker cultures, why my laptop is covered in security-conference-related stickers, etc. etc. During this process there is always the implied threat of imprisonment without due process. All my stuff is gone through. They find nothing, because I am not a threat in any way, other than that I freely associate with those aspects of society and culture which 'the mainstream' find mysterious, confusing, and scary.
So, I don't go to the USA much. Its about as much fun to get there as driving into a brick wall.