I wouldn't touch the topic of Bitcoin with a 10 foot pole around strangers, let alone people with the authority to deport me. I still can't explain it to my friends in a way without making it sound suspicious.
(As an American, I hate crossing the UK border just as much as crossing the US border. What's the point of being in the EU if you aren't going to act like it? :)
I've been told my visa wasn't valid because there should be a blue copy instead of a red copy (he was wrong - as the INS eventually told me) I have been told that I'm only allowed so many visa waiver visits (wrong), that I can't visit my companies US office under visa waiver (wrong)
It's as if every time an airbus landed at a US airport it was upto the baggage handler to decide if it met FAA requirements