In all my travels, I have found immigration officials to be unfailingly courteous but I've observed they quickly become testy if they detect someone attempting to pull a fast one.
I started going to England as a child, and I can remember coming there from Holland when I was about 17 - I had recent stamps in my passport from Bulgaria and Turkey -and being asked the purpose of my trip and how long - I said something like I wanted to go to Stonehenge and would be in England six weeks - and the customs officer got out a big black book and started looking in it. At that point, my mother came up behind me and asked,”is everything all right?” and made it clear that she was my mother. He shut the book and waved us through.
My point is that they have always been stiff and if you say something idiotic, you can get in trouble. That officer was just minutes away from having me searched, and I would have been in a lot of trouble if he had.
Thank you.