I just recently came back from Japan. It was my first time leaving the country. Going into Japan was great, very straightforward, polite, and fast. I actually had a question; they ask "Where are you staying?" on the form, but I didn't know. I was meeting my girlfriend in-country, and she had made all of our reservations, and I forgot to ask her for a copy. The woman smiled and said "No problem, just write Tokyo" and that was it.
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.
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.
I visited Japan last year, and while I was fingerprinted and photographed, the process was very quick. I spent about the same amount of time at the customs official's desk as I did when I returned home to the US, where I was asked the typical none-of-their-business questions about my trip.
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.
> They ask "Where are you staying?" on the form, but I didn't know.
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.
Counter-experience: I walked through customs with just a backpack after being in Europe for 2.5 weeks. Guy looks at me and says "you didn't check any bags?" and I responded "I travel light," with a bit of a grin on my face. He says "welcome home." It was a touching moment.
I usually print out my hotel confirmation email before I leave to bring along, but often I forget, especially when I'm on a biz trip and transportation to my hotel has been prearranged. Really, no one cares. I'd wouldn't suggest admitting to not knowing, but instead just write something -- anything -- down. No customs official knows the name of every hotel in the nearby city (pick an obvious one... "Tokyo Marriott" or whatever). If you're asked about the address, you can just say you're not sure, but you have a car waiting to pick you up.
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.
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.