I've never had an awful lot of sympathy for people who assume that because they know they're not up to anything dodgy that the immigration people will know too. I was married in the US and knew that when I went on my honeymoon I better have letters from my employer in the UK as well as my return ticket or I might get refused entry to the US when I was heading back to where my new wife lived. Predictably I ended up in secondary checks, they were fine and I moved on. I've had the same half a dozen times when traveling for funerals, weddings or just holidays. My wife was also interrogated by British immigration for two hours before we got married. Again they want proof that you're up to no harm and it's your job to do that.
A former colleague of mine tried to get his American girlfriend to the UK and they had massively different stories when she arrived. She got a 1-month holiday visa and a severe threat that both (he was a US citizen) would be deported if she overstayed by even a single day.
The onus is on the person crossing the border to know what they're doing. There's plenty of info, particularly on going to the US and no excuse not to prepare, especially if you're going for work not a holiday.
A former colleague of mine tried to get his American girlfriend to the UK and they had massively different stories when she arrived. She got a 1-month holiday visa and a severe threat that both (he was a US citizen) would be deported if she overstayed by even a single day.
The onus is on the person crossing the border to know what they're doing. There's plenty of info, particularly on going to the US and no excuse not to prepare, especially if you're going for work not a holiday.