Coming back into America was terrible. I did answer these questions, and the officer tried to imply that I had tripped up, and was getting in trouble. (I live in PA, but my ticket was back to LAX only.) Then, while walking through to the 'collect your baggage' part, another officer stopped me, told me to get in a different line, since I'd collected no checked baggage. I told him I didn't have any, his eyes narrowed, and he started asking me more questions. I was like "Dude, I'm a guy. I have this huge backpack. I was only gone a week. Why would I need a suitcase?" and after a few more questions finally let me go.
I don't fly unless I absolutely have to. It's just not worth the hassle.
http://laist.com/2009/05/05/14_birds_found_tied_to_legs_of_s...
They see that stuff all the time, and they get suspicious about unexplained features of baggage.
I fly in and out of the country all the time (I believe I've returned the the US five times this year alone). I only ever have a backpack and it's not huge and I never check any luggage. I'm not dressed in business clothes, nor do I look particularly affluent. My passport is fully of "dangerous" countries (Colombia, Guatemala, China, Russia...) and is as beat up an scruffy looking as I am.
I have never once has trouble returning to the US.
In fact, I flew back from Mexico (several years ago, but post 9/11) without anything but a driver's license and even then didn't have any problems other than answering some reasonable questions.
I've heard anecdotally that it's more difficult for foreigners entering the US, but that's to be expected. Pretty much every country on the planet is harder for non-citizens to enter.
Oh, and for the record, I'm in Japan right now (for the first time) and their CBP was far more serious than anywhere else I've been and took longer to process everyone than anywhere I've been except Dulles (fuck that airport). I was finger printed and photographed (yes, yes, I know the US does this for non-citizens too) and this is highly atypical.
So there we are... more anecdotal non-evidence.
Actually, this reminds me of my return from a business trip to Amsterdam a couple years ago. The customs official made some kind of drug-related joke/question, which I didn't respond to (aside from just smiling slightly). It made me a bit uncomfortable and felt like he was trying to get me to slip up and say something I'd regret.
Note: as you might have suspected, if the situation was reversed you wouldn't get away so easily. Suppose your girlfriend is not American and she visits in you US. She must answer that question. Otherwise she might have to go thru some hassle or even be denied entry.
Now, this is from experience as a US citizen traveling to Asia and Europe. I have no idea if US border control verifies the name and address of your hotel before letting you through.
During which time you have sniffer dogs almost clawing you and really aggressive questioning. I'm sure this must have a negative effect on the tourism industry as most people I know have had similar experiences.
I've just come back from traveling around Asia and they seem to take the opposite approach and employ polite and helpful people to work in border security, often when you're traveling this is the first impression you get of a country and bad experiences really leave a bad taste.
Of course they're increasingly exporting that to their allies in Europe too, the UK is especially bad in this regard.
Citizens are in a slightly better position as the fellow demonstrated but the U.S. border is worse than any of the other 35 or so that I have crossed.
In my experience it depends largely on the airport you're flying into in the US. Dulles, Philly, and any of the NYC airports all see to be the worst. Seatac, SFO, Houston, and LAX aren't really that bad in my experience.