Thank goodness I never read this or anything like it when I was dating a Brit. We met through mutual friends while he was here in the states, and a few months later, after I graduated from college and before I was officially job hunting, I went to visit him for 3 weeks. No one ever warned me about immigration!!
I wasn't technically detained, but I was answering questions standing at that stupid podium thing for at least 20 minutes. They asked questions about me (work or lack thereof, schooling, what was my degree in, what did I plan to do with it, where did I live in the states, had I always lived there, was I planning to move), about him (his job, how much money he made, where did he live, did he own his flat, etc... and when I said he was a journalist, it seemed like their questions got even more intense about him), how much money I had in my accounts... when I mentioned my daughter (they hadn't asked if I had children, surprisingly), then the questions started about her... how old, where was she staying, why wasn't she with her father, where was her father, why didn't I have contact with him, when did I plan to contact him again...
It was very, very ugly. I was able to keep good humor about it, because I had NO IDEA that they could possibly turn me away for just going on a 4 week holiday and having a place to stay with a guy I wanted to get to know a bit better... had I known, I'd have probably been in tears, they'd have probably thought I was hiding something, and I'd have probably been sent back. Gah!!